How to choose an ecommerce marketing agency: 8 checks before you sign

Agency websites tend to say the same things: results-driven, data-led, a dedicated team. None of it helps you choose. What helps is a short list of checks you can run before you sign, each with a clear pass or fail. This is ours, and we expect prospects to run it on us too.

1. Who owns the ad accounts and the data

Your Google Ads account, your Meta ad account, your Analytics property and your Search Console should be set up in your name, with the agency added as a user. If the agency owns them, the history of what worked leaves when the agency does, and the next one starts from zero.

Google’s rules back you up. Its third-party policy says an agency must give you the customer ID of your Google Ads account when you ask, so you can contact Google directly. An agency that hesitates over that request is already outside Google’s rules.

2. Whether you can see the real ad spend

You should always be able to tell what Google charged apart from what the agency charges. Under the same policy, an agency that sends monthly reports must show costs, clicks and impressions for the account, report the exact amount Google charged without its own fees mixed in, and tell you about any separate management fee in writing before your first purchase and on every invoice.

Reporting costs higher than Google charged, or misreporting clicks and impressions, is prohibited outright. The simplest check takes five minutes a month: log in to the account yourself and compare the spend with the report.

3. Proof you can trace back

Ask for case studies with named clients and figures, then ask where each figure came from. A number the client published, or one you can see in an account the agency runs, can be checked. A round number on a slide with no client named cannot.

Testimonials need the same care. Since 6 April 2025 the Digital Markets, Competition and Consumers Act has made fake reviews, and incentivised reviews that hide the incentive, banned practices in the UK. The CMA’s guidance expects any business that publishes reviews to take steps to prevent and remove fake ones. A wall of five-star quotes with no surnames or companies asks you to take a lot on trust.

4. Anyone who guarantees rankings

Google’s own advice on hiring an SEO puts it in one line: “No one can guarantee a #1 ranking on Google.” That is from Google Search Central. A guaranteed position, or a set number of leads promised before anyone has looked at your site, means the promise came first and the plan will come later.

The same applies to anyone who says buying Google Ads will lift your organic rankings. Google’s policy lists that claim as prohibited when it is false.

5. What the first conversation is about

A good first call is mostly questions about your business: what you sell, what you can afford to pay for a customer, who your competitors are, and where your sales come from today. Google suggests asking a prospective SEO about its experience in your industry and your country, and how it measures success. If the call is mostly a pitch, expect the work to be built around the agency’s packages.

6. Who does the work

Ask who will run your account day to day, and whether any of it is outsourced. Many agencies use freelancers or white-label partners. That can work well, as long as you know.

It also matters for data. If the agency handles your customers’ personal data, UK GDPR requires a written contract that covers what it may do with the data, how it keeps it secure, and when it may pass work to subcontractors. The ICO lists what that contract must include.

7. How you can leave

Read the notice period and the minimum term before anything else in the contract. A long lock-in puts the risk on you. Then check what you keep when you go: account access, the website files and logins, any content written for you, and the tracking setup. Anything that stays with the agency, you were only renting.

8. Whether the company checks out

For a UK limited company, Companies House shows the registered office, the directors, when it was set up and whether its accounts are filed on time, all free. Check that the company name on the contract matches the business you have been talking to.

The checklist on one page

Run it on us

We are an ecommerce marketing agency based in Birmingham, and some of our answers are already public. Our case studies name each client and say where every figure was published. The first consultation is free, and there are no charges for the first month. For the rest, book a call and ask us all eight.