The verdict in three sentences
In London in 2026, a performance audit costs GBP 1,200 to 3,000 and the optimization work GBP 3,000 to 9,000, images and caching first. For a slow B2B site the gains are direct: TTFB from 1.4s to 0.3s, +17% page views and -28% bounce rate. Every 100 ms saved turns into page views and baskets for an e-commerce merchant.
Where a site's speed is won
B2B site performance breaks into three links: the server (TTFB, cache, CDN), the assets (images, fonts, JS) and the render (hydration, third-party scripts). In London, a poorly configured WooCommerce or Magento store often shows a 1-1.5s TTFB: that's the first loss, invisible but massive.
| Lever | Typical gain | Budget (GBP) | Effort |
|---|---|---|---|
| Server cache + CDN | TTFB -70 to -80% | 1,200 - 3,300 | medium |
| WebP/AVIF image compression | weight -50 to -65% | 800 - 2,200 | low |
| Lazy-load + optimized fonts | LCP -1 to -2s | 600 - 1,800 | low |
| JS / third-party cleanup | INP -40 to -60% | 1,200 - 3,700 | high |
| Audit + costed plan | diagnosis | 1,200 - 3,000 | - |
For a mid-sized B2B store in London, the realistic budget is around GBP 5,700 audit included, over 3 to 5 weeks.
London vs Rennes comparison (2026)
In Rennes, an equivalent optimization costs EUR 2,000-6,000 (about GBP 1,700-5,100), thanks to markedly lower day rates. Technical scope and expected gains stay identical.
| Item | London (GBP) | Rennes (EUR excl. tax) |
|---|---|---|
| Performance audit | 1,200 - 3,000 | 700 - 1,900 |
| Image + cache optimization | 3,000 - 9,000 | 2,000 - 6,000 |
| Target TTFB | 0.3 s | 0.3 s |
| Work timeline | 3 - 5 wk | 2 - 3 wk |
| Day rate | 700 - 1,200 GBP | 500 - 800 EUR |
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Mini case study
Mark, who runs a B2B supplies platform in London, has a site at 30,000 visits/month, a 1.4s TTFB and a 58% bounce rate. He invests GBP 1,800 on the audit and GBP 3,900 on the work, i.e. GBP 5,700. TTFB drops to 0.3s, page views rise +17% and bounce falls to 42% (-28%). Across 30,000 visits at 2.1% conversion, the smoother journey adds about +110 orders/month; at a GBP 180 average B2B order and 25% margin, that's about GBP 5,000 extra margin per month. The investment pays back in under 4 weeks.
FAQ
What's the difference between performance and Core Web Vitals? Core Web Vitals (LCP, INP, CLS) are standardized Google metrics. Overall performance also covers TTFB, total weight and third-party scripts: a site can have good CWV yet still be slow on the server side.
Is TTFB really that important? Yes, it's the starting point of the whole load. Going from 1.4s to 0.3s mechanically improves LCP and perceived speed, with a direct effect on bounce rate.
How long does the work take? From 3 to 5 weeks for a mid-sized B2B store in London. Very large or multilingual catalogues may need 5-7 weeks.
Do I need to change host? Often, cache/CDN optimization is enough. But a saturated shared host may force an upgrade (VPS or managed) to hold a TTFB under 0.4s.
Do the gains really impact sales? Yes. In B2B, -1s of load time commonly yields +5 to +15% page views and a clear bounce drop, so more completed baskets.
Let's scope your project. Send us your site URL and platform (WooCommerce, Magento, other): we'll measure TTFB and quote audit + work. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
