London's Ultimate Meta Ads Agency Vetting Guide

Hiring a Meta ads agency in London is a bit of a minefield, tbh. It's full of agencies with fancy offices in Canary Wharf or Soho that talk a good game but have never actually scaled a business like yours. They show you glossy reports full of 'impressions' and 'reach', but when you look at your bank account, nothing's changed. The truth is, most London founders get burned because they ask the wrong questions and fall for the wrong promises.

The single biggest mistake is thinking location matters. You're not looking for a new mate to go for a pint with; you're looking for a specialist who can navigate the brutal auction of Facebook and Instagram ads and deliver a positive return. Whether their office is in London or Leeds is completely irrelevant. What matters is their track record.

So, how do I spot an agency that's actually good?

It's simpler than you think. You ignore 90% of what they say and focus on one thing: their case studies. Not vague testimonials, but detailed breakdowns of campaigns for businesses similar to yours. You're looking for proof.

When we talk to a potential client, say a B2B SaaS founder, they dont care that we know London. They care that we've worked on campaigns like the one that got a medical job matching SaaS from a £100 CPA down to just £7. Or the one that generated 1,535 trials for another B2B SaaS client. These are real numbers that translate to real business growth.

Here’s what to look for in a case study:

• -> Niche Relevance: Have they worked with London-based eCommerce brands, FinTech startups, or B2B service firms like yours before? An agency that's great at selling dresses online might be useless for generating high-value B2B leads.
• -> Real Metrics: Are they talking about ROAS (Return On Ad Spend), CPA (Cost Per Acquisition), and revenue generated in Pounds Sterling (£)? Or are they waffling about clicks and impressions? If it's the latter, they're hiding something.
• -> Transparency: Do they explain the strategy? Do they talk about the challenges and how they overcame them? A good case study isn't just a victory lap; it's a demonstration of their problem-solving ability.

Another massive green flag is an agency that offers a free, no-obligation strategy session or account audit. This is the ultimate "show, don't tell" move. We do this for nearly every potential client. It's a 20-30 minute call where we'll look at their existing ads (if they have any) and give them actionable advice they can implement straight away. It's the easiest way for you to gauge their expertise. If an agency tries to gatekeep their knowledge until you've signed a contract, they're probably not confident in it. Finding the right partner is a challenge, which is why we've put together a comprehensive guide on how to choose the best paid ad agencies in the UK.

What kind of results should I realistically expect in the London market?

This is where things get interesting. London is a competitive market, so costs can be higher. But the value of a customer is often higher too. Anyone promising you a specific ROAS before they've even seen your business is lying. It just doesn't work like that.

Performance depends on your niche, your offer, and your price point. For a B2C eCommerce store, a 2-5% conversion rate is typical. For a high-ticket B2B service, it's going to be much lower. For instance, our best consumer services campaign for a home cleaning company achieved a cost of just £5 per lead, while for an HVAC client in a competitive market, a lead cost of around $60 was a great result.

Here's a rough idea of what you might see, based on our experience with UK campaigns:

But obsessing over the Cost Per Lead (CPL) is a rookie mistake. The real question isn't "how low can my CPL go?" but "how high a CPL can I afford to acquire a great customer?" This is where understanding your Customer Lifetime Value (LTV) becomes critical. For many London tech founders, getting a handle on their B2B paid ads ROI starts with this exact calculation.

Let's do the maths. If a customer is worth £10,000 to your business over their lifetime, paying £300 for a qualified lead that converts at a 1-in-10 rate is a bargain. You're spending £3,000 to make £10,000. That's the kind of maths that scales businesses. Most agencies won't have this conversation with you.

To make this tangible, I've built a simple calculator below. Play around with your own numbers. This will tell you what you can *really* afford to spend to get a new customer and still be wildly profitable.

So what does a good agency actually do?

A good agency doesn't just 'run ads'. They become a strategic partner. The first thing we do is get obsessed with a client's ideal customer. Not demographics, but their actual pains, fears, and goals. Once you understand that, you can write ad copy that actually connects.

Then it's about structure and relentless testing. Most accounts we audit are a mess. One campaign, a few ad sets with broad interests, and a couple of ads that have been running for six months. It's lazy. A proper Meta Ads campaign involves a tiered structure:

• -> Top of Funnel (ToFu): Reaching new people who have never heard of you. This involves testing dozens of audiences - interests, behaviours, lookalikes of your best customers.
• -> Middle of Funnel (MoFu): Re-engaging people who have shown some interest but haven't been to your site. Maybe they watched 50% of your video ad.
• -> Bottom of Funnel (BoFu): This is the money-maker. Retargeting website visitors, people who added to cart but didn't buy, etc. This is where you convert interest into revenue.

For a niche like a SaaS ads agency in London, the funnel is even more important because the sales cycle is longer. You have to nurture leads, not just go for the hard sell immediately.

Here’s what that looks like visually. It’s a process of filtering and escalating commitment.

Within each of these stages, we are constantly split-testing. Different ad copy, different images, different videos, different offers. You have to find the combination that resonates. An ad that works brilliantly for a tech crowd in Old Street might completely flop with finance professionals in the City. There's no silver bullet, just a process of rigorous, data-driven optimisation. It takes time and expertise.

How much will a good London agency cost me?

Agency pricing is another area where there's a lot of smoke and mirrors. Generally, you'll see a few models:

1. Monthly Retainer: A fixed fee each month. This is common and provides predictability. For a decent London agency, you'd be looking at anywhere from £1,500 to £5,000+ per month, depending on the complexity and ad spend.
2. Percentage of Ad Spend: The agency takes a cut of what you spend on ads, typically 10-20%. This model aligns their incentives with spending more, which isn't always the same as getting better results.
3. Hybrid/Performance Model: A lower base retainer plus a performance bonus for hitting certain targets (e.g., a certain ROAS or number of leads). This can be a great model as it aligns incentives perfectly.

Be very wary of cheap agencies. If someone quotes you £500 a month, they're either outsourcing the work to someone who doesn't know what they are doing, or they'll spend about two hours a month on your account. You get what you pay for. The cost of a good agency should be seen as an investment, not an expense. The cost of a bad agency is the fee plus all the ad spend they waste for you. If you want a more detailed breakdown, we have a whole guide on London PPC agency costs.

My final advice: a step-by-step vetting process

To cut through the noise, you need a process. Don't get distracted by fancy websites or sales pitches. Follow these steps, and you'll find a partner that can actually help you grow.

I've mapped it out in a simple flowchart below. This is the exact process you should follow.

To make it even clearer, I've broken down what you should be looking for at each stage.

Choosing the right agency is one of the most important marketing decisions you'll make. Get it right, and you unlock a predictable, scalable channel for growth. Get it wrong, and you'll waste thousands of pounds and months of your time.

The expertise is out there, but it's rarely found in the agencies with the biggest marketing budgets or the fanciest offices. It's found with the specialists who are obsessed with data, strategy, and most importantly, their clients' results.

If you're a London-based founder and you're tired of wasting money on Meta ads that don't deliver, you might benefit from some expert help. We offer a completely free, no-strings-attached 20-minute strategy session where we can look at your specific situation and give you some clear, actionable advice. If we think we can help, we'll tell you how. If not, you'll still walk away with valuable insights. Feel free to reach out to schedule a consultation.