Measurable speed optimisation for RGP Market
- Client
- RGP Market
- Industry
- E-commerce
- Year
- 2026
- Related service
- Site speed
- GTmetrix
- Lighthouse
- Core Web Vitals
- Frontend optimisation
The problem
In the initial GTmetrix test on July 4, 2026, the site scored 39% Performance and had a 10.5-second LCP. The goal was to improve loading experience without changing the store's visual identity or core features.
Approach and technical decisions
Starting point
The GTmetrix report from July 4, 2026 showed 39% Performance, 89% Structure and Grade E. The main bottleneck was a 10.5-second LCP, while CLS was already 0.01.
Post-optimisation GTmetrix result
In the August 16, 2026 retest, Performance reached 69%, Structure 88% and Grade C. LCP fell to 2.1 seconds, TBT dropped from 368 to 242 milliseconds, and CLS stayed at 0.01.
Lighthouse result
The Lighthouse run recorded:
- Performance: 97
- Accessibility: 88
- Best Practices: 96
- SEO: 92
- FCP: 0.7s
- LCP: 0.8s
- TBT: 50ms
- CLS: 0.03
- Speed Index: 1.7s
Summary
This project demonstrates measurement-led optimisation: the baseline was recorded first, then the same tools and metrics were used for comparison. The result can therefore be described with numbers rather than a generic “faster website” claim.
GTmetrix results depend on the London test server and report settings. Lighthouse can vary by device, network, browser and active extensions; the screenshot itself recommends an extension-free or Incognito run.
Results
Before/after figures use the same tool and test settings; single figures describe the delivered scope.
GTmetrix Performance
+77%69
Largest Contentful Paint
−80%2.1 s
Total Blocking Time
−34%242 ms
Cumulative Layout Shift
0%0.01
Site speed optimisation
Finding what is actually slow and getting LCP, INP and CLS into the green — reported as a before and after number, not a Lighthouse screenshot.