Choosing an SEO agency is one of the more nerve-wracking decisions a business owner makes, largely because the outcomes are hard to judge in advance. You cannot test-drive rankings the way you can test-drive a car, and by the time you realise something has gone wrong, you may have lost six months and several thousand pounds. The good news is that most bad agencies give themselves away early. They share a recognisable set of behaviours, and once you know what to look for, you can filter out the worst offenders in a single discovery call.
This guide walks through the SEO agency red flags that matter most for UK businesses, why each one is a problem, and the practical questions you can ask to separate a genuine partner from a fee-collecting machine. We will be honest throughout, including about where the industry as a whole falls short.
Red flag one: guaranteed number one rankings
If an agency promises you the top spot on Google for your main keyword, walk away. No legitimate SEO provider can guarantee a specific ranking, because no one controls Google's algorithm except Google. Search results are personalised, they shift constantly, and they are influenced by hundreds of signals the agency has no authority over.
What a good agency can promise is a sound process: technical fixes, quality content, sensible link acquisition, and honest reporting on progress. What it cannot promise is that you will outrank a competitor with a fifteen-year-old domain and a national brand budget by next quarter.
There is a subtler version of this trick. Some agencies "guarantee" a first-page ranking but only for absurdly niche phrases nobody searches, such as "affordable emergency plumber in a specific SW postcode open Sunday". Ranking first for a term with two searches a month is worthless. Always ask what keyword the guarantee applies to and check its search volume before you are impressed.
Red flag two: long lock-in contracts
SEO takes time, and any honest agency will tell you results typically build over three to six months and mature over twelve. That is a fair reason to ask for a reasonable commitment. It is not a reason to trap you in a twelve or twenty-four month contract with punitive exit clauses.
The uncomfortable truth is that lengthy contracts protect the agency, not you. If the work is good, you will stay voluntarily. If it is bad, a long contract simply forces you to keep paying for underperformance. We built NetTrackers on month-to-month terms precisely because we think the results should keep you, not the paperwork. If an agency needs a two-year lock-in to retain clients, ask yourself what that says about their confidence in the work.
What a fair commitment looks like
A reasonable arrangement gives you a short notice period, usually thirty days, clear ownership of everything created on your behalf, and no penalty for leaving beyond that notice. Crucially, you should own your website, your content, your Google Business Profile and any accounts set up in your name. Some agencies keep these assets hostage so that leaving means starting from scratch.
Red flag three: no transparency or reporting
You are entitled to know what you are paying for. A trustworthy agency reports regularly, in plain English, and shows the connection between the work done and the outcomes achieved. That means rankings for your target terms, organic traffic trends, and, most importantly, leads or sales, not just vanity metrics.
Be wary of reports that drown you in data while hiding the numbers that matter. A dashboard showing "impressions up 400 per cent" means little if enquiries are flat. Ask to see a sample report before you sign. If it is a screenshot of a third-party tool with no commentary, that is a red flag. If the agency cannot explain what they did last month and why, that is worse.
Questions that reveal transparency
Ask directly: "Can I see the Google Search Console and Google Analytics data myself?" A good agency gives you access to your own accounts. A poor one keeps you locked out so you cannot verify their claims or take the data with you when you leave.
Red flag four: black-hat tactics
Black-hat SEO refers to techniques that break Google's guidelines to game rankings quickly. They can work for a short while, then trigger penalties that tank your visibility, sometimes for good. Recovering from a manual penalty can take many months and considerable expense, so the short-term gain is rarely worth it.
Common black-hat signs include cloaking (showing Google different content than users see), doorway pages built only for search engines, hidden text stuffed with keywords, and automated content spun out at scale with no editorial care. If an agency boasts about "secret methods" or "loopholes", assume they mean techniques that will eventually cost you.
Buying links
Link building is legitimate when it earns genuine editorial mentions from relevant, reputable sites. Buying links in bulk from private blog networks or link farms is not. Google explicitly treats paid links that pass ranking signals as a violation. A large batch of cheap links might nudge rankings briefly, but Google's link-spam systems are increasingly good at ignoring or penalising them. If an agency promises "100 backlinks for £150", those links are almost certainly worthless or harmful.
Keyword stuffing
Cramming a target phrase into every sentence made sense in 2010. Today it reads badly to humans and signals low quality to Google. Modern search understands meaning and context, so content should be written for people first. If an agency's sample content repeats "best accountant London" awkwardly a dozen times, their playbook is out of date.
Red flag five: suspiciously cheap packages
We have all seen the adverts: "SEO from £99 a month". It is worth being blunt here. Real SEO involves skilled people spending real hours on strategy, technical work, content and outreach. At £99 a month, there is no room for any of that. What you actually get is an automated tool spraying low-quality directory links and a monthly PDF that looks like work.
Cheap packages are not just poor value, they can actively harm you if they rely on spammy links. You then pay a competent agency to clean up the mess. For most small UK businesses, a genuine SEO retainer starts in the region of several hundred pounds a month and rises with ambition and competitiveness. That does not mean expensive equals good, but it does mean rock-bottom pricing almost always signals corner-cutting.
Red flag six: poor communication and vague deliverables
If it is hard to get a straight answer during the sales process, when the agency is trying to win you, it will be worse once you have signed. Slow replies, no named point of contact, and evasiveness about what exactly they will do are all warning signs.
Vague deliverables are a particular menace. "We will optimise your site and build your authority" tells you nothing. Ask what that means in practice this month. A good answer sounds like: "We will rewrite your five service pages, fix the crawl errors flagged in the audit, add schema markup, publish two articles, and earn three relevant links." That is something you can hold them to.
The tell of the single strategy
One thing worth checking is whether the people selling to you are the people doing the work, or at least closely connected to them. Some agencies split sales, strategy and delivery so completely that no one owns the outcome. At NetTrackers we deliberately keep it to one team and one strategy so that the person who understands your goals is the person shaping the work.
How to vet an SEO agency properly
Vetting does not need to be complicated. A short, structured approach filters out the majority of poor providers.
Ask for relevant case studies and references
Request examples from businesses similar to yours in size and sector, then ask to speak to one of those clients. An agency confident in its work will happily arrange it. Look for case studies that show leads and revenue, not just rankings, and be sceptical of results with no context or dates.
Check their own online presence
An agency that cannot rank its own site or maintain a decent reputation is not a strong advertisement for its services. Read independent reviews, check whether their blog offers genuine insight, and see whether they practise what they preach.
Insist on a documented plan
Before committing, ask for an outline of the first ninety days. It does not need to be a fifty-page document, but it should show that they have looked at your site, understood your market, and formed a view. Beware anyone who wants your money before they have looked at anything.
Understand who owns what
Confirm in writing that you own your website, content, and all accounts. Confirm the notice period. Confirm what happens to the work if you leave. These are boring questions, and boring questions are exactly the ones dishonest agencies dislike.
Frequently asked questions
How long should I give an SEO agency before judging results?
Give it three to six months for early signals such as improved rankings on less competitive terms and rising organic traffic, and twelve months for meaningful commercial impact. That said, you should see evidence of activity and sensible reporting from month one. Patience on results is fair; patience on communication is not.
Are long contracts ever justified?
Occasionally a large, complex project warrants a defined term, but for most businesses a rolling monthly arrangement with a short notice period is both fair and safer. It keeps the agency accountable and lets you leave if the work disappoints.
Is cheap SEO ever worth it?
Very rarely. Genuine SEO requires skilled human effort, and that has a cost. Bargain-basement packages usually rely on automation and spammy links that add little value and can cause harm. It is generally better to do less at a proper standard than a lot at a damaging one.
What is the single most important question to ask?
"Can you show me exactly what you will do in the first month, and can I see your reporting?" The answer, or the reluctance to answer, tells you almost everything about how the relationship will run.
Where NetTrackers fits
We built NetTrackers to be the opposite of the red flags above: month-to-month terms with no long lock-in, one team and one strategy so someone genuinely owns your results, and reporting that connects our work to your leads. If you want your foundations checked before committing to anyone, our SEO audit service and free SEO audit are a sensible starting point. From there, our organic SEO and local SEO teams can pick up whichever areas matter most.
Not sure whether your current agency is delivering? Book a free strategy call and we will give you an honest second opinion, with no contract and no pressure.