Consent Mode v2 and GA4 compliance for a B2B website in London: cost

The verdict in three sentences

Without Consent Mode v2, a London consulting firm spending 3,500 GBP a month on Google Ads runs its campaigns with a growing share of invisible conversions and shrinking remarketing audiences. Compliance costs between 2,000 and 5,000 GBP, plus a certified CMP at 0 to 35 GBP a month and, optionally, server-side tracking at around 1,800 GBP. Google's modelling can recover up to 30 % of lost conversions, provided the banner follows ICO and UK GDPR guidance.

What happens when Consent Mode v2 is missing

Since March 2024, Google requires advertisers targeting users in the European Economic Area and the UK to send two extra signals, ad_user_data and ad_personalization, to use measurement and remarketing features. Without them, conversions from visitors who refuse cookies vanish from reports, audience lists stop filling and automated bidding optimises on a reduced sample.

On a consulting firm's B2B site, where a lead can be worth several thousand pounds, cookie refusal rates in the UK often sit between 30 and 50 % when the banner offers a "Reject all" button at the same level as "Accept all", as the ICO expects. Without modelling, up to half of your conversions escape Google Ads.

How much compliance costs

The work has four building blocks: choosing and configuring a Google-certified consent management platform, setting up Consent Mode v2 in Google Tag Manager, auditing existing GA4 and Google Ads tags, then checking that conversions come through. For a 30 to 80-page site with two or three forms, the budget stays under control.

Advanced mode, which sends cookieless pings when visitors refuse, feeds Google's modelling. It must be described in your privacy notice and validated with your DPO or legal adviser, as its interpretation under PECR and UK GDPR is still debated.

ICO points to check

The banner must make refusing as easy as accepting, with no pre-ticked boxes and no "continued browsing means consent". No advertising cookie may be set before the choice. Consent is typically refreshed every 6 to 12 months as a rough guide. Finally, proof of consent must be stored, which certified CMPs handle.

Mini case study

Daniel, marketing director of a 60-consultant firm in London, spends 3,500 GBP a month on Google Ads and sees 25 measured leads a month, while his CRM records 40 from the campaigns. After a 3,500 GBP compliance project with advanced Consent Mode v2 and a 25 GBP monthly CMP, Google Ads recovers through modelling about 30 % of the missing conversions, or 4 to 5 extra visible leads. Automated bidding optimises better and cost per lead falls from 140 GBP to 118 GBP as a rough estimate. Over 12 months the saving is close to 3,000 GBP, covering most of the initial investment, not counting the lower enforcement risk.

FAQ

Is Consent Mode v2 mandatory?

It is not required by law, but Google has required it since March 2024 to measure and remarket to users in the EEA and the UK. Without it, you lose roughly 30 to 50 % of signal.

Basic or advanced mode?

Basic blocks all tags before consent; advanced sends cookieless signals that feed modelling. Advanced recovers more conversions but must be documented and legally validated.

Which CMP should we choose?

One listed among Google's certified partners, with a visible reject button and proof-of-consent storage. Prices range from 0 to 35 GBP a month for a mid-traffic B2B site.

Does server-side tracking bypass consent?

No. It improves reliability and control over the data sent, but visitor choices must always be respected. Allow about 1,800 GBP and 10 to 45 GBP a month.

How long does compliance take?

Between 5 and 10 working days for a standard B2B site, including 2 to 3 days of data checks in GA4 and Google Ads.

Let's scope your project. Send us your website address and monthly Google Ads budget for an audit and an estimate between 2,000 and 5,000 GBP, with compliance delivered in 2 weeks. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.