The £180k/month a fashion brand recovered from LCP fixes alone

In late 2025 we audited a mid-market UK fashion brand doing £3M in annual revenue. Their mobile LCP was 4.2 seconds. Industry benchmark for fashion ecommerce is 2.5s. Google’s “good” threshold is 2.5s. Their competitors were hitting 1.8s.

Six weeks of work later, their LCP was 1.8s. Mobile conversion rate lifted 11.4%. Desktop lifted 6.2%. Monthly revenue recovered: £180,000, from identical traffic and ad spend.

The diagnosis

PageSpeed Insights had been telling the previous agency that images were the problem. That was half right. The full picture required looking at the waterfall chart in Chrome DevTools with real 4G throttling — not the synthetic test environment PageSpeed uses.

What we actually found, in order of impact:

• Hero image was a 2.4MB JPEG served unresized across devices — 72% of LCP time.
• Web fonts were blocking render with a 1.8s timeout rather than swapping after 100ms — 15% of LCP.
• Critical CSS was bundled with the main stylesheet, forcing a 680ms blocking request.
• Three third-party scripts (chat widget, review platform, analytics proxy) were loading synchronously in the head.
• Their CDN was set to a single UK origin with no European or US edge caching.

The five fixes

1. Image pipeline

AVIF with WebP fallback, responsive srcset at 5 breakpoints, explicit width/height, and for hero only. Hero image dropped from 2.4MB to 68KB.

2. Font loading

Self-hosted WOFF2 with and font-display: swap. Removed Google Fonts dependency. Eliminated 1.2s of render blocking.

3. Critical CSS

Inlined above-the-fold styles in