The verdict in three sentences
A legacy website on Drupal 7 or an old WordPress is a growing liability: unsupported core, security holes and page loads that push mobile visitors away before the first screen. Migrating to a modern stack costs GBP 18,000-45,000 in London for 2026, but a botched move can cost 10-30% of organic traffic, so the migration plan matters as much as the build. The decisive factor is not looks but security, performance and rankings, which directly drive your inbound pipeline.
Legacy migration budget from London in 2026
Cost depends on the current stack, content volume and integrations. Here are the reference ranges.
| Migration type | Scope | Cost 2026 | Timeline |
|---|---|---|---|
| Small legacy site | 10-25 pages, modern CMS | GBP 18,000-25,000 | 8-10 weeks |
| Mid legacy site | 25-80 pages, integrations | GBP 25,000-35,000 | 10-13 weeks |
| Large legacy site | 80+ pages, multilingual | GBP 35,000-45,000 | 13-16 weeks |
| Drupal 7 to headless | End-of-life core, full reprise | GBP 30,000-45,000 | 12-16 weeks |
| Audit + migration plan | Technical + SEO diagnosis | GBP 2,000-4,000 | 1-2 weeks |
Moving off an end-of-life CMS is not cosmetic: it closes security exposure and unlocks the performance that drives ranking and conversion.
Legacy vs modern stack: the measured gap
Legacy sites carry hidden costs in security, speed and SEO. Here is the typical gap after migration.
| Criterion | Legacy site | Modern stack | Effect |
|---|---|---|---|
| Core support | End of life | Actively maintained | -Security risk |
| Mobile responsive | Partial/none | Yes | -Mobile bounce |
| Homepage weight | 4-6 MB | < 1 MB | Fast loads |
| LCP mobile | 4-8 s | 1.2-2 s | +Ranking, +conversion |
| Google indexing | Patchy | Structured, indexed | +Inbound |
| Monthly maintenance | High, fragile | GBP 300-900/mo | Up to date, secure |
A site loading in 2 seconds instead of 8 can double or triple the number of visitors who reach the contact form.
Mini case study
James, operations director at a professional-services firm in London, runs a Drupal 7 site of 60 pages, end-of-life and slow, generating 12 enquiries per month. Mobile LCP is 5 s. We scope a migration to a modern headless stack at GBP 32,000 over 12 weeks, with a full 301 map and SEO reprise. Target: lift enquiries from 12 to 20 qualified per month. If the firm converts 1 in 4 enquiries into a GBP 6,000-margin engagement, the 8 extra enquiries add roughly GBP 12,000 of monthly margin. The migration pays back in under 3 months, security remediation aside.
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FAQ
How much does a legacy website migration cost from London?
Between GBP 18,000 and GBP 45,000 depending on stack, page count and integrations. A Drupal 7 end-of-life migration to headless typically lands at GBP 30,000-45,000. An audit at GBP 2,000-4,000 scopes the budget first.
Why migrate off Drupal 7 or an old WordPress now?
Because end-of-life cores no longer get security patches, leaving you exposed, and the performance drags down rankings and conversion. Every month on a legacy stack adds security and pipeline risk.
Will migration hurt my SEO?
It can if unplanned: a botched move costs 10-30% of organic traffic for 2-4 months. With a complete 301 map, kept high-performing URLs and Search Console monitoring, loss stays under 5% and recovers in 6-8 weeks.
How long does a legacy migration take?
Budget 8-16 weeks depending on size and integrations. A 10-25 page site migrates in 8-10 weeks; a large multilingual or Drupal 7 site runs 13-16 weeks including reprise and QA.
Can I keep my domain and email during migration?
Yes: the domain and professional email addresses are preserved, and the cutover is done without service interruption or loss of your @yourcompany addresses.
Let's scope your project. Tell us your current CMS, page count and integrations, and we will benchmark your legacy migration. 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.
