01
Technical SEO audits
Crawl, index, render, Core Web Vitals field data, structured data, internal links, hreflang, redirects, logs and robots.txt, in one prioritised list.
Elgrith London · Technical SEO
Crawl, render, index and Core Web Vitals, audited, fixed and re-tested. An SEO audit London teams can act on, scoped with a London client partner and delivered by engineers at our New Delhi HQ.
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FIG 02 · Quick answer
What does a technical SEO agency do?
A technical SEO agency makes sure search engines and AI crawlers can find, render and index your site. Elgrith runs SEO audits for London businesses, then fixes crawl and indexing issues, Core Web Vitals including INP, JavaScript rendering, redirects and robots.txt rules, through our London client-partnership centre with delivery from our New Delhi HQ.
- Projects delivered since 2015
- 1,000+
- Clients served worldwide
- 250+
- Engineers who ship what the audit finds
- Audit + fix
- Fixed written quotes
- GBP
Why it matters now
What Google reads, how fast it must load, and who else is crawling.
Three dated facts most technical SEO audits still miss, each checked on its source on 24 Oct 2026.
01
2MB
Googlebot reads only the first 2MB
Google says Googlebot crawls the first 2MB of a supported file type, uncompressed, and the first 64MB of a PDF. Heavy HTML and inline scripts can push content past the cut-off.
Source: Google Search Central, Googlebot (updated 3 Feb 2026, checked 24 Oct 2026)(opens in a new tab)02
200 ms
A good INP, at the 75th percentile
web.dev sets good Core Web Vitals at LCP of 2.5 s or less, INP of 200 ms or less and CLS of 0.1 or less, measured at the 75th percentile of real visits. INP replaced FID on 12 Mar 2024.
Source: web.dev, Web Vitals (updated 31 Oct 2024, checked 24 Oct 2026)(opens in a new tab)03
Separate
Search crawlers are not training crawlers
Google says Google-Extended “does not impact a site’s inclusion in Google Search”. OpenAI likewise separates OAI-SearchBot, for ChatGPT search, from GPTBot, for training.
Source: Google, common crawlers (updated 15 Oct 2026, checked 24 Oct 2026)(opens in a new tab)
What you get
Technical SEO for London businesses
For London ecommerce brands, SaaS companies, professional services firms and publishers whose sites have grown faster than their foundations. One team audits, fixes and re-tests, in UK English.
02
Crawling and indexing fixes
Duplicate URLs, canonicals, soft 404s, parameter sprawl and pages stuck as “Discovered – currently not indexed”, fixed at the source.
03
Core Web Vitals and INP
LCP, INP and CLS measured from real-user data and fixed template by template, from image delivery to long JavaScript tasks.
04
JavaScript rendering
Server-side or static rendering where it matters, so content and links are in the HTML Googlebot receives, not only after scripts run.
05
Robots.txt and AI crawlers
Rules for Googlebot, Google-Extended, OAI-SearchBot and GPTBot that match what you want from search and AI training.
06
Structured data
JSON-LD for organisations, products, articles, FAQs and breadcrumbs, generated from your data and tested per template.
07
Migrations and redesigns
Redirect maps, staging checks and post-launch monitoring when you change platform, domain or URL structure.
08
Hreflang for UK and international sites
en-GB alongside other markets, with self-referencing tags, return links and an x-default that validate.
Deliverables
11
deliverables, in writing
Included in every build, written into your fixed quote before work starts.
SEO audit for London businesses
What our SEO audit covers, and what you get
Our SEO audit is a prioritised ticket list, not a 90-page PDF. Every finding names the affected URLs, the fix, who should make it and how we will re-test it.
| Area | What we check | What you get |
|---|---|---|
| Crawling | Crawl paths, status codes, robots.txt, XML sitemaps and server logs | URLs wasting crawls, and the rules to stop it |
| Indexing | Canonicals, noindex, duplicates and Search Console page indexing | The pages missing from Google, and why |
| Rendering | HTML vs rendered DOM, JavaScript links and the 2MB limit | Content Googlebot can’t see, by template |
| Core Web Vitals | LCP, INP and CLS from field data at the 75th percentile | The slowest templates and the fixes that move them |
| Structured data | JSON-LD validity and fit for each page type | Errors fixed and missing types added |
| Links and hreflang | Internal links, orphan pages, redirects and hreflang tags | Link and redirect fixes that reach deep pages |
| AI crawlers | Robots rules for Google-Extended, OAI-SearchBot and GPTBot | A written policy that matches your goals |
Want a first look before a full audit? Our free SEO audit covers the headline issues. Full audits are scoped in writing with a fixed quote in GBP.
Process · 6 steps
How we work with London teams.
A London client partner, reviews in your working day and a written scope before anything is changed. Your Search Console, analytics and CMS stay in your name.
- Step 01
Free call
Your site, stack, traffic trends and recent releases, discussed by video in your working day.
- Step 02
Audit
Crawl, logs, Search Console and field data reviewed, then a prioritised ticket list ranked by traffic at stake and effort.
- Step 03
Fixed written quote
A written scope with the fixes, access, milestones and a fixed quote in GBP. Timelines are agreed in your written scope.
- Step 04
We fix what we find
Our engineers implement in Next.js, WordPress, Shopify, Webflow or custom stacks, or review your developers’ pull requests.
- Step 05
Re-test
Every fix re-crawled and re-checked in Search Console and field data after release, with results reported against the baseline.
- Step 06
Ongoing checks
Release reviews and re-audits after major changes, as agreed in your written scope.
What you get
Included in a technical SEO engagement
No prices on this page, on purpose. Every audit and fix programme gets a written scope and a fixed quote in GBP after a free call, so you know the full cost before work starts.
11items
- Written scope and fixed quote in GBP
- Full crawl and log-file review
- Prioritised ticket list with acceptance criteria
- Core Web Vitals plan by template
- JavaScript rendering checks
- Robots.txt and AI crawler policy
- Structured data fixes
- Redirect and migration checks
- Fixes implemented or reviewed by our engineers
- Re-test report against the baseline
- Search Console, analytics and CMS in your name
AI crawlers: who to allow
Search crawlers and AI training crawlers are different bots.
Blocking the wrong user agent can remove you from search; allowing the wrong one may let your content train models you never chose. Google says Google-Extended “does not impact a site’s inclusion in Google Search nor is it used as a ranking signal” (common crawlers page, updated 15 Oct 2026). OpenAI separates OAI-SearchBot, which decides whether you appear in ChatGPT search, from GPTBot, which crawls for model training; ChatGPT-User visits only when a person asks, so robots.txt may not apply to it. OpenAI says robots.txt changes can take about 24 hours to reach its search systems. We write a crawler policy with you, then set robots.txt to match. Checked 24 Oct 2026.
- Googlebot allowed, so Search and AI Overviews can use your pages
- Google-Extended allowed or blocked, without affecting Search
- OAI-SearchBot allowed if you want to appear in ChatGPT search
- GPTBot allowed or blocked for training, separately
- Rules tested after every robots.txt change
Working with a London team
London partner. UK working day.
A client partner at our London client-partnership centre runs your project on UK time. Audits and fixes are delivered from our New Delhi headquarters, which is 4.5 hours ahead of London in summer and 5.5 hours ahead in winter. Call times are agreed in your written scope.
A London client partner
One person owns your account from the London centre: scope, priorities, reviews and sign-off. You never chase a ticket queue.
Reviews in your working day
Audit walkthroughs and fix reviews are booked in your working day, by video, with written notes for anyone who could not join.
New Delhi delivery
Audits, engineering and testing happen at our New Delhi headquarters, the team behind 1,000+ projects since 2015.
In person if agreed
Sessions run remotely by default. If your project needs an in-person workshop in London, we agree it in the scope first.
New Delhi · HQLondon
Live: today’s working days in London and New Delhi, adjusted for British Summer Time automatically.
Your team
London partnership. New Delhi engineering.
Client partnership
London
UK & Europe · Client partnerships
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Headquarters
New Delhi
Headquarters · Design & engineering
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Elgrith in London
Technical SEO for London and the UK
From City professional services firms to Shoreditch start-ups and national retailers, UK teams use Elgrith for audits that end in shipped fixes. These are the areas we serve; we do not claim a London address.
01
Ecommerce and retail
Faceted navigation, product variants, out-of-stock pages and Core Web Vitals on category templates, on Shopify, WooCommerce or custom stacks.
02
SaaS and tech
JavaScript-heavy marketing sites, documentation and help centres that need to render for Googlebot and appear in AI answers.
03
Professional services and publishers
Large content libraries, author and topic pages, structured data and migrations from older CMSs without losing hard-won rankings.
Serving businesses across London and beyond
- City of London
- Westminster
- Shoreditch
- Canary Wharf
- Camden
- Southwark
- Greater London
- Across the UK, remotely
Core Web Vitals and INP
Core Web Vitals thresholds, and how we fix them
Google’s Core Web Vitals are judged on real visits at the 75th percentile, so a fast test on your laptop isn’t enough. INP replaced FID as a Core Web Vital on 12 Mar 2024.
| Metric | Good (75th percentile) | What usually fixes it |
|---|---|---|
| LCP: Largest Contentful Paint | 2.5 s or less | Faster server responses, a preloaded hero image, less render-blocking CSS |
| INP: Interaction to Next Paint | 200 ms or less | Shorter JavaScript tasks, less third-party script, lighter event handlers |
| CLS: Cumulative Layout Shift | 0.1 or less | Sizes set on images, embeds and ads; fonts that don’t shift text |
From web.dev, Web Vitals (updated 31 Oct 2024) and the web.dev blog on INP (updated 31 Jan 2024), checked 24 Oct 2026. For speed work beyond SEO, see our website speed optimisation service.
JavaScript rendering and the 2MB limit
Making sure Googlebot sees your content
Googlebot reads the first 2MB of an HTML file, uncompressed, and fetches each CSS and JavaScript file separately under the same limit. Google also notes that pages returning a non-200 status may not be rendered at all. We check both.
06items
- Main content and links present in the server HTML, not only after scripts run
- HTML kept well under 2MB uncompressed, without huge inline scripts or data blobs
- Important pages return 200, so they reach rendering
- Robots meta tags in the head, where Google expects them
- Internal links as real anchor tags with href values
- Rendered HTML compared with the raw HTML for every template
Site migrations and redesigns
Redesigning or replatforming without losing rankings
Google says to expect temporary ranking fluctuation during a site move, and to keep redirects as long as possible, generally at least a year. We plan the SEO side from the first workshop.
06items
- A full redirect map from crawls, logs, analytics and backlinks
- Permanent server-side redirects (301 or 308), with no chains
- Staging crawled and tested before launch
- Canonicals, hreflang and sitemaps updated to the new URLs
- Change of Address in Search Console for domain moves
- Monitoring of indexing and traffic after launch
Technical SEO or full-service SEO?
Technical SEO agency or a full-service London SEO agency?
We are a technical SEO specialist on this page. If you need content, local search and the wider London SEO programme, our London SEO page covers it, and the same team works on both.
| Technical SEO agency | Full-service SEO | |
|---|---|---|
| Best for | Sites with crawl, index, speed or migration problems | Businesses that need content and local visibility too |
| Main work | Audits, engineering fixes, re-tests | Keyword strategy, content, local SEO and technical basics |
| Who ships changes | Our engineers, or your developers from our tickets | Writers, SEO specialists and developers |
| Where to start | This page, or a free SEO audit | Our full-service SEO page for London |
Elgrith does not sell link building or digital PR links, and we don’t run PPC or Google Ads. We hold no Google Partner or other partner status.
Rules and dates
Technical SEO rules and dates: what changed and when
The dated guidance this page relies on, so your team can check it. Each item was read on its source on 24 Oct 2026; we re-check before your scope is signed.
| Date | Change | What it means for your site |
|---|---|---|
| 12 Mar 2024 | INP replaced FID as a Core Web Vital | Responsiveness is judged on every interaction, at the 75th percentile |
| 20 Nov 2025 | Google moved its crawler docs to a new crawling site | Old bookmarks and audit checklists may cite outdated pages |
| 18 Dec 2025 | Google noted that non-200 pages may not be rendered | Status codes decide whether JavaScript content is seen at all |
| 3 Feb 2026 | Googlebot page states the 2MB limit (64MB for PDFs) | Keep HTML lean and content early in the file |
| 24 Mar 2026 | Google documented robots meta tags outside the head | Keep robots meta in the head so it is read as you intend |
| 20 Aug 2026 | Site moves guidance updated | Keep redirects as long as possible, generally at least a year |
| 15 Oct 2026 | Common crawlers page updated | Google-Extended doesn’t affect inclusion or ranking in Search |
Sources: web.dev (Web Vitals; INP blog), Google Search Central (Googlebot; documentation updates; site moves), Google’s common crawlers page and OpenAI’s overview of its crawlers, all checked 24 Oct 2026.
Tech & tools
The tools we audit with
Standard tools your team can use after we hand over. We name tools we use; we hold no partner status with any of them.
- Google Search Console
- Screaming Frog
- Chrome UX Report
- PageSpeed Insights
- Lighthouse
- Chrome DevTools
- GA4
- Bing Webmaster Tools
- Next.js
- WordPress
- Shopify
- Webflow
FAQ
Frequently asked questions
What London businesses ask us about technical SEO.
It makes sure search engines and AI crawlers can find, render and index your site. That means auditing crawling, indexing, JavaScript rendering, Core Web Vitals, structured data, redirects and robots.txt rules, then fixing what the audit finds. Elgrith does both: the audit and the engineering.
Let’s find what’s holding your site back, and fix it.
Book a free call. Tell us about your site, your stack and your recent releases, and we will send a written audit scope with a fixed quote in GBP.
Free 30-minute call · London
- Fixed written quote, no surprises
- NDA before discovery
- You own the code and IP
Book a free call
OpenPick a day. You'll choose a time in your own time zone on the next step.