UK Founder's Guide to Hiring a Paid Ads Firm

Right then. You're a UK founder, you've got a business that's working, and you've decided it's time to pour some fuel on the fire with paid ads. The problem is, the moment you start looking for a "paid advertising firm," you're hit with a wall of noise. SEO-juiced lists of "Top 10 UK Agencies," slick London firms with beanbags and kombucha on tap, and solo consultants promising the earth. It’s a mess, and it’s designed to confuse you into making a quick, often wrong, decision.

Most founders approach this process backwards. They look for an agency to solve a problem they haven't properly defined themselves. They ask "who is the best?" instead of "who is the best for *me*?". Let's sort that out. This isn't about finding the agency with the best sales pitch; it's about finding a genuine partner who can become an extension of your team and actually make you money. It requires you to do some work upfront, but that work will save you thousands of pounds and months of frustration down the line.

So, what's the first mistake everyone makes?

They trust Google's search results. Typing in "best paid ads agency UK" will show you the agencies that are best at SEO, not necessarily the best at running paid ads. It's a classic case of mistaken identity. The skills required to rank a website are completely different from the skills needed to build and scale a profitable ad campaign. Many of the big-name firms you see ranking at the top are sales machines. They have slick processes for getting you to sign a contract, but then you're often handed off to a junior account manager juggling 20 other clients. Your business becomes just another number on a spreadsheet.

The size of an agency, its location, or its polished website tells you almost nothing about its ability to get you results. I've seen incredible results come from tiny, two-person teams working remotely, and I've seen massive, award-winning agencies burn through a client's budget with nothing to show for it. You need to ignore the vanity metrics and focus on the only thing that matters: expertise. Specifically, expertise in solving the kind of problem your business has for the kind of customer you want to attract. This means you need to be looking for specific proof and case studies that align with your goals, not just a fancy client logo list.

How do I know what I even need?

This is the critical bit of homework you must do *before* you even think about talking to an agency. If you go into a conversation without your own numbers, you're at their mercy. They'll set the benchmarks, they'll define success, and you'll have no way of knowing if you're getting a good deal or being taken for a ride. You need to understand the fundamental economics of your own business.

The most important number you need to know is your Customer Lifetime Value (LTV). How much gross margin does a typical customer generate for you over their entire relationship with your business? This number dictates how much you can afford to spend to acquire a customer (your Customer Acquisition Cost, or CAC). A common rule of thumb is to aim for an LTV:CAC ratio of at least 3:1. So, if your LTV is £3,000, you can afford to spend up to £1,000 to acquire that customer and still have a healthy business model.

Forget generic calculators online. Let's work it out right here. Tweak the sliders below to match your business's numbers.

Once you have this number, the entire conversation changes. You're no longer asking "how many leads can you get me?". You're stating, "My LTV is £9,000. I need to acquire customers for under £3,000. Can you build a strategy to achieve that?". It completely flips the power dynamic. You are now in control, and you can instantly weed out any agency that can't speak your language or that balks at being held to a real business metric. This is how you move from hiring a service provider to finding a growth partner.

Okay, I have my numbers. How do I actually find and vet these people?

This is where you need a systematic process. Don't just book a few calls and go with your gut. Your gut can be fooled by a charming salesperson. You need a framework to compare agencies on an equal footing. It's a bit like a sales funnel, but you're the one doing the qualifying.

Here’s a visual breakdown of how I'd approach it. This isn't about creating work for yourself; it's about being efficient and making sure you only spend your valuable time talking to genuinely strong contenders.

Step 1: The Longlist. Your goal here is quantity with a hint of quality. Forget "paid ads agency London" and get specific. Search for things like "meta ads agency for UK saas" or "google ads for ecommerce subscription box". Look at who is writing insightful content, not just ranking for keywords. Ask other founders in your network or in communities like Toptal or Indie Hackers. The goal is to find 10-15 names that seem plausible on the surface.

Step 2: The Shortlist. Now you get ruthless. This is where you spend an hour or two digging. The number one thing to look for is relevant case studies. And I don't just mean they've worked in "eCommerce". Have they worked with brands with a similar price point and average order value to yours? For a SaaS business, have they worked with a similar sales cycle and pricing model? I remember one campaign where we took a medical job matching SaaS from a £100 CPA down to £7. That's a specific result for a specific type of business, and it's far more valuable than a generic claim of "we get great ROI". If their case studies are vague and full of marketing fluff, bin them. If they can't show you real, tangible results that mirror the ones you want, they're not the right fit. You're looking for a specialist, not a generalist. At this stage, you should have narrowed your list down to your top 3-5 contenders. A good guide to vetting agencies will always tell you to prioritise depth of experience over a broad client list.

What questions should I ask on the discovery call?

This is where you separate the talkers from the doers. Too many founders let the agency lead this call, sit through a 20-minute slide deck, and then meekly ask about pricing. Wrong. You need to take control and turn it into an interview. Here are the questions that will reveal everything you need to know:

• "Based on what you know about my business, what would be your strategic approach for the first 30-60 days?" - A good partner will have already looked at your website and have some initial thoughts. They should talk about audience testing, creative angles, and setting up proper tracking. A bad partner will give a vague answer like "we'll start by doing an audit and then build some campaigns".


• "Can you walk me through your process for creative testing?" - This is huge. Many agencies just set and forget. You want to hear about a structured process. How do they test headlines, images, videos, and audiences? How do they decide when a test is a winner or a loser? If they can't answer this clearly, they're just guessing with your money.


• "Who will be my day-to-day point of contact, and who will actually be working on my account?" - You need to know if you're talking to the A-team salesperson who will then pass you off to a junior. Ask about the experience of the person who will be in the weeds of your account. It's perfectly fine to ask to meet them before signing.


• "Can you show me an example of a monthly report you provide to clients?" (with sensitive data redacted, of course) - This cuts through the bullshit. Does their report focus on real business metrics like ROAS, CPA, and revenue, or is it full of vanity metrics like impressions and clicks? Is there analysis and commentary, or is it just a data dump? You're paying for their brain, not just their ability to export a dashboard. A good agency provides insights, not just numbers.


• "What do you need from me to be successful?" - This is a brilliant question. It shows you see this as a partnership. A great agency will have clear answers: they'll need your insights on customers, quick feedback on creative, and access to your sales data to close the loop. An agency that says "don't worry, we'll handle everything" is a massive red flag. That's not a partnership; that's abdication. And it rarely ends well.

The answers to these questions will be far more telling than any polished sales deck. You're listening for process, for strategic thinking, and for a genuine interest in your business. A good discovery call should feel like a strategy session, not a sales pitch. It’s a key part of learning how to choose an agency that actually drives profit.

The Proposal: How to spot a winner (and a loser)

After the calls, you'll receive the proposals. Most will look the same: a bit about them, a list of services, and a price. This is where you need to look for the details. A winning proposal is a reflection of the conversation you just had. It should reference your specific goals, your LTV, and your target CPA. It should outline a clear, phased approach that directly addresses the strategy they discussed on the call. It should feel like a bespoke plan for your business, because it is.

A losing proposal is a template. It's full of generic industry stats and buzzwords. The "strategy" section is just a list of channels they'll use. It feels impersonal and like it could have been sent to any other business. This is a sign that they didn't really listen and that you'll be getting a cookie-cutter service. Tbh, it's a definite red flag for us if a proposal doesn't feel tailored.

Pay close attention to the pricing structure. The most common models in the UK are:

• Flat Retainer: A fixed fee per month. Simple and predictable. Good for businesses that need consistency, but make sure the scope is clearly defined.
• Percentage of Ad Spend: The agency takes a cut of what you spend on ads (usually 10-20%). This can align incentives, as they make more when you spend more (which you'll only do if it's working). But watch out for agencies that push to increase spend without a corresponding increase in results.
• Performance-Based: A lower retainer plus a bonus for hitting certain targets (e.g., a fee per lead, or a percentage of revenue generated). This is the holy grail for alignment, but it's rarer and usually reserved for clients with a proven offer and significant scale.

There's no single "best" model; it depends on your stage and goals. The important thing is that it's clear, transparent, and you understand exactly what you're paying for. Debating between hiring an agency vs building an in-house team often comes down to these costs and the expertise you get for your money.

I've signed the contract. Now what?

The work isn't over. The first 90 days are critical for setting the tone of the relationship. A good onboarding process should be thorough. They should be scheduling a deep-dive kickoff call, getting access to all your accounts, and installing tracking pixels. They should be hungry for information about your customers, your past marketing efforts, and what makes your product special.

Your role is to be an active partner. Be responsive. Provide them with your best customer insights. Give quick and clear feedback on the ads they create. The best results always come from a collaborative relationship where the founder's deep knowledge of the business is combined with the agency's deep knowledge of the ad platforms. It's a two-way street. If you just throw the keys over and expect them to work magic in a vacuum, you'll be disappointed. Effectively managing the agency relationship is just as important as the initial hire.

In the end, choosing a paid ads firm is one of the most significant marketing decisions you'll make. Don't rush it. Follow a structured process, trust the data over the sales pitch, and prioritise genuine, relevant expertise above all else. Find a partner who is as obsessed with your business metrics as you are, and you'll have a powerful engine for growth. Get it wrong, and you'll just be lighting money on fire. The choice is yours.

I've detailed my main recommendations for you below in a final checklist. Use this as your guide through the process.

Navigating this landscape, especially in the competitive UK market, can be tough. It requires a level of diligence that many founders, busy with a million other things, simply don't have time for. If you've read through this and feel you'd rather have an expert partner guide you, that's what we're here for. We offer a free, no-obligation strategy session where we can dive into your specific business, your numbers, and what a realistic growth plan looks like. It's a chance to get a second opinion and see what a truly data-driven approach feels like.

Hope this helps!