Google Analytics Tracking: The GA4 Setup Guide for UK Businesses
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Most small business websites in Northern Ireland and across the UK are either running no analytics at all or running GA4 incorrectly. The tracking code is there, but the data is incomplete, the goals are unconfigured, and the consent layer is missing entirely. That means every marketing decision is based on guesswork.
This guide walks through how to set up Google Analytics tracking properly in 2025 and beyond, covering GA4 configuration, Google Tag Manager, PECR-compliant consent setup, conversion tracking, and verifying that everything is working. Whether you manage your own website or work with an agency, understanding this setup makes every other part of your digital marketing more accountable.
Getting analytics right is one of the first things ProfileTree addresses when auditing a new client’s website. The data you collect from day one shapes every SEO, content, and paid campaign decision you make afterwards.
What Is Google Analytics Tracking in the GA4 Era?
Google Analytics tracking is the process of collecting data about how visitors find and use your website. Every time someone lands on a page, GA4 records what they do: where they came from, which pages they visit, how long they stay, and whether they take any meaningful action, such as submitting a contact form or making a purchase.
Universal Analytics, the previous version most people used until mid-2023, is now retired. If your account still references a UA-XXXXXX property ID, that property stopped collecting data in July 2023 (or July 2024 for GA4 360 accounts). GA4 is the current standard and works differently in some important ways.
The core difference is how data is collected. UA used a session-based model. GA4 uses an event-based model, meaning everything on your site — page views, clicks, form submissions, video plays — is treated as an event. This gives you more granular data, but it also means configuration needs more attention to get right from the start.
Measurement ID vs Tracking ID: What Changed and Why It Matters
Many SME website owners searching for their “tracking ID” find instructions that no longer apply. This is one of the most common sources of confusion when setting up analytics tracking.
The old Tracking ID format was UA-XXXXXXX-X. That format is dead. GA4 uses a Measurement ID in the format G-XXXXXXXXXX. If you or your developer are pasting in a UA code anywhere in 2025, nothing will be tracked.
To find your Measurement ID in GA4: navigate to Admin, select your GA4 property, then click Data Streams. Select your web data stream, and your Measurement ID (beginning with G-) will be displayed at the top right. This is the code that goes into your website or into Google Tag Manager.
Keeping these identifiers straight matters especially if you are migrating an older WordPress site. Many plugins were originally set up with UA IDs and need to be updated to GA4 Measurement IDs. This is something ProfileTree’s web development team routinely catches during site audits.
How to Set Up Google Analytics Tracking: Step by Step
There are two main approaches to installing GA4: manual installation using the gtag.js snippet and installation via Google Tag Manager. For most SME websites, Google Tag Manager is the better choice. Here is why, and how both work.
Option 1: Manual Installation (gtag.js)
Manual installation means pasting the GA4 tracking snippet directly into the <head> section of every page on your site.
- Go to GA4 Admin > Data Streams > select your web stream
- Copy the Global Site Tag (gtag.js) snippet
- Paste it into the
<head>section of your site, ideally before the closing</head>tag - If you use WordPress, a plugin such as Site Kit by Google can handle this without touching the theme files
This works, but it has a significant limitation: every time you want to add a new tracking event, you or your developer needs to edit the code again. It also makes it harder to implement consent management correctly.
Option 2: Google Tag Manager (Recommended)
Google Tag Manager acts as a container. Instead of editing your website code every time you want to change your tracking, you manage everything from a single interface. GA4, conversion tracking, remarketing pixels, and cookie consent all live inside Tag Manager.
- Create a Google Tag Manager account at tagmanager.google.com
- Create a new Container for your website
- Paste the GTM snippet into your site — one snippet goes in the
<head>, one in the<body> - Inside GTM, create a new Tag: choose Google Analytics: GA4 Configuration
- Enter your Measurement ID (G-XXXXXXXXXX)
- Set the trigger to fire on All Pages
- Preview and test in GTM’s Preview Mode before publishing
Once GTM is in place, any future changes to your analytics setup — new goals, new tracking events, A/B test tags — can be made without touching your website’s code. For businesses that work with a web development agency and a separate marketing team, this separation of responsibilities is genuinely useful.
Comparison: Manual vs Google Tag Manager
| Manual gtag.js | Google Tag Manager | |
|---|---|---|
| Setup speed | Faster initially | Slightly longer setup |
| Future changes | Requires code edits | All managed in GTM |
| Consent Mode | Harder to implement | Built-in support |
| Multiple tags | Gets messy quickly | Centralised and clean |
| Recommended for | Simple static sites | Most SME websites |
The UK Compliance Layer: PECR, UK GDPR, and Consent Mode V2
This is the section most guides skip, and it is the most important one for any business operating in the UK or Ireland.
Google Analytics uses cookies and collects personal data, including IP address information and browsing behaviour. Under the UK GDPR and the Privacy and Electronic Communications Regulations (PECR), you cannot set non-essential tracking cookies without the user’s prior explicit consent. Analytics cookies are classified as non-essential. This means GA4 must not fire until a user has actively accepted cookies.
Failing to comply is not a theoretical risk. The ICO (Information Commissioner’s Office) in the UK and the DPC (Data Protection Commission) in Ireland have both investigated and fined organisations for analytics deployments that bypass consent. For UK businesses post-Brexit, PECR and the UK GDPR (which mirrors the EU version in most respects) both apply.
What Is Consent Mode V2 and Why Does It Matter?
Google introduced Consent Mode V2 in March 2024 as a mandatory requirement for advertisers using Google’s advertising and measurement products in the EEA and UK. It allows GA4 and Google Ads tags to operate in a limited, privacy-safe mode when a user declines cookies, using modelled data to fill reporting gaps rather than simply going dark.
Without Consent Mode V2 implemented, your reporting loses significant accuracy when users decline your cookie banner. More importantly, without it, your GA4 setup is not compliant with the current Google policy for UK-based advertisers.
To implement Consent Mode V2 correctly with Google Tag Manager:
- Choose a certified Consent Management Platform (CMP) — tools such as CookieYes, Usercentrics, or OneTrust integrate with GTM
- Configure the CMP to pass consent signals to GTM before any tags fire
- Set your GA4 tag in GTM to respect those consent signals using the Consent Initialisation trigger
- Test using GTM’s Preview Mode to confirm tags are not firing before consent is granted
Many SME websites in Northern Ireland have a cookie banner that looks compliant but isn’t technically set up correctly. The banner appears, but the analytics tags fire on page load regardless of the user’s selection. For help assessing your current setup, our guide to designing GDPR-compliant web forms covers the broader data collection and consent principles, and our GDPR training for teams is worth considering if your marketing team handles consent decisions.
The ethics and legalities of digital marketing are covered in depth elsewhere, and consent management sits at the centre of this for any UK business running paid or organic campaigns.
How to Verify Your GA4 Tracking Is Working
Installing the tag is step one. Confirming it is actually collecting clean data is step two — and plenty of businesses skip it entirely.
Use GA4 Real-Time Reports
In GA4, navigate to Reports > Real-Time. Open your website in a separate browser tab and navigate around. Within a few seconds you should see your session appear in the Real-Time overview. If nothing appears after 30 seconds, the tag is not firing correctly.
Use Google Tag Assistant
Google Tag Assistant (available as a Chrome extension and via tagassistant.google.com) lets you inspect which tags are firing on any given page and whether they are sending data correctly. On each page load, it shows you the GA4 configuration tag, any event tags, and their status (firing correctly, firing with errors, or not firing at all).
Tag Assistant is the fastest way to diagnose a broken tracking setup. Common errors it flags include mismatched Measurement IDs, tags firing only in preview mode, and consent blocks preventing the tag from loading.
Check Your Data Streams for Active Status
In GA4 Admin > Data Streams, your web stream should show a green indicator and display recent activity. If it shows no data received in the last 48 hours and you have real traffic, something in the configuration is wrong.
Setting Up Conversion Tracking and Goal Events
Raw traffic data tells you how many people visited. Conversion tracking tells you what they did that mattered.
In GA4, conversions are built from events. Some events are collected automatically through Enhanced Measurement (such as page views, scrolls, outbound clicks, and file downloads). Others need to be configured manually, particularly the ones most important to an SME: contact form submissions, phone number clicks, quote requests, and purchase completions.
Mark Key Events as Conversions
In GA4 Admin > Events, you can toggle any event as a Key Event (GA4’s term for what UA called a conversion). Once marked as a key event, it will appear in your Conversions report and can be imported into Google Ads for campaign optimisation.
For a typical SME service business in Northern Ireland, the events worth configuring as conversions include:
- Contact form submission (confirm page view or form_submit event)
- Phone number click
- Email link click
- Quote request or booking form completion
- Brochure or PDF download
Use GTM to Track Form Submissions
If your contact form does not redirect to a thank-you page, tracking form completions requires a custom event in GTM. Set up a Trigger in GTM to fire on form submission success, create a GA4 Event Tag that sends the event name (for example, contact_form_submit) to GA4, and then mark that event as a Key Event in the GA4 interface.
Understanding which pages generate the most enquiries directly informs your digital marketing strategy and is the data your SEO team needs to prioritise content investment. ProfileTree’s digital training programmes teach marketing managers and business owners how to build and read these reports themselves — see our digital training services if that would be useful for your team.
Advanced Tracking: Enhanced Measurement, Audiences, and GA4’s AI Features
Once your base setup is working and consent is configured correctly, GA4 offers a range of capabilities that most SME websites do not use.
Enhanced Measurement
In your GA4 Data Stream settings, Enhanced Measurement automatically collects several event types without any code changes: page views, scrolls (when a user reaches 90% of a page), outbound clicks, site search, video engagement (for YouTube embeds), and file downloads. Enable this in your Data Stream settings and review which events are relevant to your site.
Audience Building
GA4 allows you to build audiences based on user behaviour — for example, users who visited your pricing page but did not submit a form, or users who watched more than two minutes of video content. These audiences can be exported to Google Ads for remarketing campaigns.
Predictive Metrics
GA4 includes machine learning features such as purchase probability, churn probability, and predicted revenue. These are most relevant for e-commerce businesses but have genuine utility for any SME that runs ongoing paid campaigns. For businesses working with ProfileTree on AI implementation, these predictive signals are worth integrating into campaign planning. Our article on training your team to work with AI covers how to build the internal capability to use data like this effectively.
Troubleshooting Common Analytics Tracking Issues
| Problem | Likely Cause | Fix |
|---|---|---|
| No data in GA4 | Tag not installed or wrong Measurement ID | Check GTM > Preview Mode; verify G- code |
| Tags firing before consent | Internal traffic is not filtered | Configure Consent Initialisation trigger in GTM |
| Inflated session counts | Form submissions are not tracking | Add internal IP to Data Filters in GA4 Admin |
| Set up a custom GTM trigger on form submit | No thank-you page redirect; GTM trigger missing | UA property is still in place |
| Events showing but not as conversions | Events not marked as Key Events | Toggle events in GA4 Admin > Events |
| Data stops appearing | Conversion import is not set up in Google Ads | Confirm you are checking the GA4 property, not the old UA |
| Discrepancy between GA4 and ads data | Conversion import not set up in Google Ads | Link GA4 to Google Ads and import Key Events |
Why Your Business Analytics Tools Need a Solid Foundation
GA4 is only as useful as the data it collects. A misconfigured analytics setup means decisions across your entire marketing operation are built on unreliable numbers.
“When we audit a new client site, a broken or misconfigured analytics setup is one of the most common findings,” says Ciaran Connolly, founder of ProfileTree. “Businesses have been making decisions about their SEO, their paid campaigns, and their content for months — sometimes years — on data they couldn’t trust. Getting the foundation right first changes everything downstream.”
The business analytics tools available to SMEs are more powerful than most companies realise. GA4 is the starting point, not the ceiling. Once you have clean conversion data flowing into GA4, you can connect Google Search Console for organic performance data, link to Google Ads for closed-loop campaign reporting, and build custom reports that answer the specific commercial questions your business needs answered.
For more on using analytics data within a content strategy, see how Google Analytics supports content marketing in our related guide.
FAQs
What is a Measurement ID in Google Analytics?
A Measurement ID is the identifier for a GA4 property, formatted as G-XXXXXXXXXX. It replaces the old Universal Analytics Tracking ID (UA-XXXXX). If you are setting up analytics tracking on any website today, you need a Measurement ID, not a Tracking ID.
Do I need a cookie banner to use Google Analytics in the UK?
Yes. Under PECR and UK GDPR, analytics cookies are non-essential and require explicit prior consent. You must not load GA4 before a user accepts your cookie notice. A banner that appears but does not actually block the tag from firing is not compliant.
What is Google Analytics Consent Mode V2?
Consent Mode V2 is a Google framework, mandatory for UK and EEA advertisers since March 2024, that allows GA4 and Google Ads tags to operate in a limited mode when consent is declined. It uses modelled data to fill reporting gaps. Implement it through a certified CMP integrated with Google Tag Manager.
How can I tell if Google Analytics tracking is working?
Open your website in one browser tab, then check GA4’s Real-Time report in another. Your session should appear within 30 seconds. You can also use the Google Tag Assistant Chrome extension to inspect which tags are firing and whether they are sending data correctly.