What website speed optimisation actually fixes
Website speed optimisation is not the same as installing a caching plugin and hoping for a better score. A useful investigation follows the request from the server through to what the visitor's browser eventually paints on screen.
We start by establishing a baseline and identifying where time and bandwidth are being lost. Common causes include oversized images, slow server responses, render-blocking CSS, JavaScript that occupies the main thread, unnecessary third-party code and fonts that delay or shift visible content.
The right fix depends on the cause. An oversized hero photograph may need resizing, compression and a more efficient format. A slow first response may point instead to PHP execution, database work, hosting configuration or missing server-side caching. Loading another optimisation plugin does not solve a server bottleneck.
You can run our free page speed checker first to see the current Lighthouse results and diagnostics for a page.
How we improve page speed without breaking the site
Performance work needs to preserve the parts of the website that make it function. Aggressively delaying JavaScript can improve a synthetic score while breaking menus, forms, analytics, checkout behaviour or consent tools. Combining and minifying assets without checking dependencies can create equally difficult faults.
Our £449 Website Speed Fix starts with a performance audit and then applies changes where they are appropriate to the site. Work can include:
- resizing, compressing and correctly loading images
- improving page, browser and server caching
- reducing or delaying unnecessary CSS and JavaScript
- optimising fonts and important above-the-fold resources
- reducing plugin or third-party script overhead
- hosting-level tuning where the environment allows it
We check the website after optimisation rather than treating a higher Lighthouse number as sufficient evidence. The service includes a before and after report so the improvement can be measured. If we cannot measurably improve the site's speed, the published Website Speed Fix includes a money-back promise.
Core Web Vitals and real user performance
Google's current Core Web Vitals are Largest Contentful Paint, Interaction to Next Paint and Cumulative Layout Shift. They measure loading, responsiveness and visual stability respectively. Google's good thresholds are LCP of 2.5 seconds or less, INP of 200 milliseconds or less and CLS of 0.1 or less, assessed at the 75th percentile.
It is important to separate laboratory testing from field data. Lighthouse runs a controlled test and is useful for diagnostics. Chrome UX Report data, which also feeds tools such as PageSpeed Insights and Search Console, reflects eligible real Chrome visits over a rolling 28-day period. A site can therefore improve immediately in a lab test while its field assessment takes longer to reflect the change.
Google states that Core Web Vitals are used by its ranking systems, but there is no single page experience signal and a good performance score does not guarantee higher rankings. Speed work should primarily make the site better for users. See our Core Web Vitals guide for a detailed explanation of each metric.
One-off website speed fix or ongoing optimisation
The one-off Website Speed Fix costs £449. It suits a site with an identifiable performance problem that needs auditing, engineering work and measurable before and after testing.
Performance can deteriorate again. New plugins can add scripts, marketing tools can introduce third-party requests, editors can upload large images and theme changes can alter critical rendering behaviour. Sites that change regularly may therefore benefit from ongoing monitoring rather than another large clean-up several months later.
The Speed Retainer costs £89 per month or £890 per year. It includes monthly Lighthouse and Chrome UX Report review, ongoing image and script optimisation, plugin bloat control, a monthly performance report and fixes for performance regressions.
For sites where the underlying hosting is part of the problem, our Managed WordPress Hosting and Hosting Support pages explain the available options without assuming that changing host is always necessary.
How to judge whether a speed fix has worked
A single performance score is useful, but it should not be the only acceptance test. We look at the metrics and diagnostics that explain what visitors experience.
- Compare like with like. Test the same URL and device profile before and after changes.
- Check the actual bottleneck. If LCP was the problem, confirm that the LCP element and its loading path improved rather than relying only on the overall score.
- Retest functionality. Navigation, forms, ecommerce functions and interactive components still need to work after scripts are delayed or removed.
- Watch field data. Where sufficient traffic exists, review subsequent Chrome UX Report and Search Console data rather than expecting 28-day field measurements to change immediately.
That combination gives a more useful answer than chasing a perfect Lighthouse score with changes that do not materially improve the website.