The verdict in three sentences
For a London SME, replacing a creaking Access database and a sprawl of shared spreadsheets with a custom web app typically costs GBP 15,000 to 30,000 for a straightforward migration, delivered in 8 to 14 weeks. The budget line most firms underestimate is data migration and cleansing (GBP 2,500 to 5,500), because a decade of free-text entry hides duplicates and broken references. Once you remove around 6 hours of weekly rekeying and gain a clean audit trail for UK GDPR, payback usually lands between 18 months and 3 years.
When Access and spreadsheets become the expensive option
Access is still bundled with some Microsoft 365 plans, and plenty of UK businesses run order books, job sheets or HR records on it. It works until it does not: each Access file is capped at 2 GB (a documented Microsoft limit), multi-user access over a shared drive is fragile, and the logic usually lives in the head of one long-serving colleague. Spreadsheets add their own risks, from overwritten formulas to five copies of the same supplier list.
Here is the hidden running cost we typically see in a 50 to 100 person London business operating this way (2026 estimates, fully loaded staff costs).
| Hidden cost | Typical volume | Estimated annual cost (2026 estimate) |
|---|---|---|
| Rekeying between files and the accounts package | 6 hours per week | GBP 8,000 to 10,000 |
| Manual month-end consolidation | 1.5 days per month | GBP 4,500 to 6,000 |
| Locked files and version conflicts | 1 to 2 hours per week | GBP 1,500 to 3,000 |
| Undetected pricing or stock errors | Hard to see until audit | Often GBP 3,000 to 6,000 |
| Key-person dependency | 1 database author | Business continuity risk |
| No access log on personal data | HR or customer files on a share | Weak position under UK GDPR accountability |
On that last point, UK GDPR expects you to demonstrate who can see personal data and why. A shared spreadsheet of employee absences cannot do that; a web app with role-based permissions and a change history can. The ICO's guidance on security and accountability is the reference to discuss with your DPO.
What a London migration costs, line by line
By a simple migration we mean consolidating 3 to 5 databases or spreadsheet families into one app with 6 to 10 business screens, user roles, dashboards and exports. Integrations with Sage, Xero or an ERP sit on top.
| Budget line | 2026 market ballpark (London, ex VAT) | What it covers |
|---|---|---|
| Discovery and wireframes | GBP 2,000 to 3,500 | User workshops, file inventory, clickable mock-ups |
| Application build | GBP 9,500 to 19,000 | Screens, roles, dashboards, CSV and PDF exports |
| Data migration and cleansing | GBP 2,500 to 5,500 | Deduplication, import scripts, reconciliation reports |
| UAT and onboarding | GBP 1,000 to 2,000 | Testing with key users, short guides, launch sessions |
| Total build | GBP 15,000 to 30,000 | 8 to 14 weeks |
| Hosting on Azure UK South | GBP 60 to 250 per month | App service, managed database, backups, monitoring |
| Support retainer | GBP 350 to 800 per month | Fixes, security patching, small enhancements |
Why Azure UK South? Many firms leaving Access already use Microsoft 365 and Entra ID, so single sign-on is straightforward and data stays in a UK region, which simplifies conversations with clients and insurers. Other UK regions or providers work too; what matters is UK or EU residency, encrypted backups and a data processing agreement with your supplier.
If you want a nearshore benchmark, Kolonell's prices for custom apps are EUR 3,810 to 6,100 (2,500,000 to 4,000,000 FCFA) for a simple app and EUR 6,100 to 10,670 (4,000,000 to 7,000,000 FCFA) for a medium-complexity app, built by a team in Dakar working on GMT. Kolonell's monthly maintenance runs from EUR 53 (Basic) to EUR 183 (Premium).
A realistic 8 to 14 week plan
| Phase | Duration | Output |
|---|---|---|
| File inventory and discovery | 1 to 2 weeks | Data map, screen list, priorities |
| Wireframes and sign-off | 1 to 2 weeks | Flows validated by 3 to 5 power users |
| Build in sprints | 4 to 7 weeks | Demo every two weeks |
| Trial data import | 1 week | Exceptions report for the business to resolve |
| UAT and cutover | 1 to 2 weeks | Final import, legacy files set to read-only |
Keep the old Access files read-only for a quarter after go-live. And if your team cannot absorb a big-bang switch, migrate by domain: purchasing first, then stock, then reporting.
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Illustrative example: Tom, finance director of a 70-person building-supplies distributor in Croydon, runs orders and stock on two Access databases and 35 spreadsheets.
- Rekeying removed: 6 hours × 46 weeks × GBP 32 = GBP 8,832 a year.
- Month-end close 1.5 days shorter: 1.5 × 12 × GBP 280 = GBP 5,040 a year.
- Pricing and stock errors avoided (prudent estimate): GBP 4,000 a year.
- Gross gain GBP 17,872, minus a GBP 550 monthly retainer (GBP 6,600): net GBP 11,272 a year.
- Investment: GBP 22,000 build + GBP 3,500 migration = GBP 25,500.
Payback in roughly 27 months, before counting the continuity risk removed.
FAQ
Should we just use Power Apps instead?
Power Apps suits simple forms if you are already on Microsoft 365, billed per user per month with public pricing that varies by plan. Past 30 to 50 users or complex business rules, a custom app is usually easier to maintain and less tied to licensing changes.
Can staff keep using Excel for analysis?
Yes. The app becomes the single source of truth and exports clean CSV or Excel files in one click. Budget 1 to 2 development days for well-formatted exports.
How long does user adoption take?
With screens modelled on real tasks and 2 or 3 onboarding sessions, most teams are comfortable within 2 to 4 weeks. Projects stall when users first see the app at UAT instead of at wireframe stage.
Does hosting have to be in the UK?
Not legally in every case, but UK or EU residency simplifies UK GDPR transfer questions and client due diligence. Expect GBP 60 to 250 a month on Azure UK South for this size of app, backups included.
What if the data is messier than expected?
It usually is, which is why a trial import runs a week before cutover. Add a 10 to 15% contingency to the migration line and name one business owner who can make decisions on conflicting records.
Let's scope your project. Send us the list of your Access databases and critical spreadsheets and we will scope the screens, the migration effort and a phased cutover plan. 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.
