How to Choose an SEO Agency: A 10-Point Checklist

Choose an SEO agency on three things. Whether they diagnosed your site before pitching, whether they can show what they shipped for a comparable client, and whether the contract lets you leave. Everything else on a pitch deck is decoration.

This guide gives you a checklist to run every shortlisted agency through, the questions that separate delivery from theatre, and the warning signs that should end a conversation early.

Start with what you are actually buying

SEO retainers are not interchangeable. One agency’s monthly fee buys technical diagnosis and on-page work. Another agency’s identical fee buys four blog posts. Both are legitimate products and they solve different problems. Before you brief anyone, decide which of these you need most: a technical problem fixed, content produced at volume, authority built through links, or a strategy you can execute yourself.

Google’s guidance on hiring an SEO makes the same point from the other side. It advises asking for a technical and search audit, and warns against anyone who promises rankings. Read it before your first pitch meeting so you know which questions are standard rather than awkward.

The ten-point checklist

1. Did they look at your site before the call?

A good agency turns up with observations. Indexation issues, a broken canonical pattern, a content gap against a competitor. An agency that arrives with a generic deck and asks what your goals are has not done the work, and that is a preview of the retainer.

2. Can they name the person who will do the work?

Pitch teams and delivery teams are frequently different people. Ask who your day to day contact is, how many accounts they carry, and whether they are in the room.

3. Do their case studies show implementation?

Ask for a case study in a comparable market and ask what was actually changed. If the answer is “we advised” rather than “we shipped”, check who is expected to do the work in your engagement.

4. How do they earn links?

This is the single fastest way to identify risk. Ask for examples of links earned in the last quarter and how they were acquired. Google’s spam policies treat buying links that pass ranking signals as a violation, and the penalty lands on your site, not the agency’s.

5. What does month one look like?

A credible answer is specific. Baseline audit, analytics and Search Console verification, a prioritised backlog, a first set of on-page fixes. A vague answer means there is no process.

6. How do they report?

Ask to see a real, anonymised monthly report. Look for whether it connects to revenue or leads. Average position and impressions alone are activity metrics, not outcomes.

7. What is the notice period?

Long minimum terms exist to protect the agency’s forecast, not your results. Terrier works with no minimum term and 60 days’ notice at any point. If an agency needs twelve months of lock-in, ask what they are worried about.

8. Who owns the accounts and the data?

Analytics properties, Search Console, tag manager and any tooling should be owned by you with the agency granted access. If the agency owns them, leaving costs you your history.

9. How do they handle your developers?

Most SEO work fails at implementation. Ask how recommendations reach a developer, in what format, and who verifies the fix went live. An agency that writes tickets rather than PDFs will get more done.

10. Are the prices real?

Published pricing is a good sign. It means the agency has decided what it is worth rather than pricing off what you look like you can pay. Terrier’s SEO retainers start from £1,250 a month, and the bands are on the SEO pricing page.

Comparing proposals fairly

Red flags that should end the conversation

• Guaranteed rankings. Nobody controls Google’s index. Google says so directly in its own hiring guidance.
• A “special relationship” with Google. There is no such thing. Google Partner status relates to Ads, not organic search.
• Cheap links at volume. Priced link packages are a policy risk you inherit.
• No access to your own data. If they will not grant you admin on your own analytics, walk.
• Reporting that only ever improves. Every real programme has a bad month. An agency that has never reported one is not reporting honestly.
• Pressure to sign this week. Discount deadlines are a sales tactic, not a commercial reality.

Run a paid trial instead of a long contract

If you are torn between two agencies, buy a piece of work from each. A technical audit or a content strategy sprint costs a fraction of an annual retainer and tells you far more than another pitch. You see how they think, how they write, how they handle questions, and whether the document is usable or generic.

This is also the cheapest way to test an agency when your budget is limited. Terrier runs standalone audits, described on the SEO audits page, and advisory engagements through SEO consultancy.

What to expect once you have chosen

Expect diagnosis before delivery. Expect the first two months to feel slower than you want, because baseline work does not produce headlines. Expect the trend to be readable at six months and the commercial case to be settled at twelve. Google states plainly that SEO changes can take months to have an effect, and any agency that has set different expectations has set you up to be disappointed.

Expect to do some work yourself as well. The agencies that produce the best results are the ones whose clients ship the recommendations. That is a partnership, not a purchase.

Write a brief before you take pitches

Most bad agency selections start with a bad brief, or with no brief at all. If every agency is answering a different question, the proposals cannot be compared and the decision comes down to who presented best.

A usable brief is one page. It states what the business sells and to whom. It names the commercial objective in revenue or lead terms rather than in ranking terms. It states the budget range, because withholding it only produces proposals you cannot afford or proposals priced at what you look like you can pay. It lists the constraints, such as a CMS you cannot change or a legal review process for content. And it names the internal owner.

Send the same brief to everyone. Ask for the same three things back: how they would diagnose the site, what they would do in the first ninety days, and what the monthly deliverables would be.

Checking references properly

Ask for two references and pick which two. An agency offering a curated list is offering its two happiest clients. Ask instead for a client in your sector, and a client who left in the last year.

When you speak to a reference, avoid asking whether they are happy. Ask what shipped last month. Ask how long a question takes to get answered. Ask what happened the first time something went wrong. Those three answers tell you more than any case study.

Check the agency’s own site as well. An agency that cannot articulate its own positioning, or whose own pages are slow and thin, is telling you something about how it prioritises work that does not have an invoice attached.

Frequently asked questions

How much should I pay an SEO agency in the UK?
Most UK businesses spend between £500 and £5,000 a month. Terrier’s SEO retainers start from £1,250 a month with no minimum term.

Should I choose a specialist or a full service agency?
Choose a specialist if your problem is narrow and technical. Choose full service if you need technical work, content and links moving together.

How long should the contract be?
Long enough to see results, short enough to leave. A rolling agreement with 60 days’ notice gives you both.

What if the agency will not share how it builds links?
Treat that as a decline. Link risk transfers to your domain, so you are entitled to know the method.

How do I know it is working before rankings move?
Look at indexation, crawl health, impressions on target queries and the rate at which fixes reach production. Those lead indicators move well before revenue does.

Related pages

• SEO pricing and packages
• SEO consultancy
• SEO audits
• Schedule a call and we will bring observations about your site.