- Companies
- Mechanics and garages
- Swansea
- South Wales Diagnostics Limited
South Wales Diagnostics Limited
- Company number
- 16287710
- Incorporated
- 3 Mar 20251 year trading
- Registered office
- 45 Pant Yr Helyg, Fforestfach, Swansea, SA5 4BJ
- Nature of business
- Maintenance and repair of motor vehicles
South Wales Diagnostics Limited is a 1-year-old private limited company registered in Swansea, company number 16287710, one of 154 vehicle repair garages in Swansea. Its next accounts are due at Companies House on 3 December 2026, and its first CT600 is due at HMRC on 2 March 2027.
Key dates
This company has not filed accounts yet. First accounts are due 21 months after incorporation, and the first period can run longer than a year.
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Where South Wales Diagnostics Limited is registered
The registered office is in Swansea (SA5), in the Swansea local authority area, Wales. Show SA5 4BJ on a map.
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What happens if South Wales Diagnostics Limited files late
Companies House charges an automatic penalty the day after the deadline, and it rises the longer the accounts are late. These are the dates for this company's accounts due on 3 December 2026.
| Companies House | Accounts delivered | Penalty |
|---|---|---|
| Up to 1 month late | 4 Dec 2026 to 3 Jan 2027 | £150 |
| 1 to 3 months late | 4 Jan 2027 to 3 Mar 2027 | £375 |
| 3 to 6 months late | 4 Mar 2027 to 3 Jun 2027 | £750 |
| More than 6 months late | From 4 Jun 2027 | £1,500 |
Penalties double if the accounts were also late the year before.
| HMRC (CT600) | From | Penalty |
|---|---|---|
| 1 day late | 1 Apr 2027 | £200 |
| 3 months late | 30 Jun 2027 | another £200 |
| 6 months late | 30 Sep 2027 | HMRC estimates the tax and adds 10% of the unpaid tax |
| 12 months late | 31 Mar 2028 | another 10% of any unpaid tax |
For returns filed on or after 1 April 2026. Late three times in a row and the £200 penalties become £1,000 each.
Company details
As held on the Companies House register.
- Company number
- 16287710
- Status
- Active
- Company type
- Private limited company
- Incorporated
- 3 March 2025 (1 year ago)
- Registered office
- 45 Pant Yr Helyg, Fforestfach, Swansea, SA5 4BJ
- Nature of business
- Maintenance and repair of motor vehicles (SIC 45200)
- Year end
- 31 March (accounting reference date)
- Accounts type
- No accounts filed yet
- Last confirmation statement
- 2 March 2026
Filing notes for vehicle repair garages
Garages hold parts stock and often own diagnostic equipment and ramps, which qualify for capital allowances.
Similar companies in Swansea
Other active vehicle repair garages registered in Swansea.
- South Wales Diesel Specialists Limited2023
- South West Injector Removal Service Ltd2024
- Sparkling Cars Ltd2020
- SPB Motors Ltd2025
- Sunnyside Autos (Gorseinon) Limited2002
- Swansea Bert MOT Limited2023
- Swansea Volkswagen Centre Limited2023
- T W K Thomas & Son Limited1999
All vehicle repair garages in Swansea · All trades in Swansea · Mechanics and garages across the UK
Frequently asked questions
When are South Wales Diagnostics Limited's accounts due?
South Wales Diagnostics Limited's next accounts are due at Companies House by 3 December 2026 (in 51 days), covering the period to 31 March 2026.
When is South Wales Diagnostics Limited's CT600 due?
The first accounts cover more than 12 months, so there are two Company Tax Returns: one for the 12 months to 2 March 2026, due by 2 March 2027, and one for the period to 31 March 2026, due by 31 March 2027. Corporation tax is payable 9 months and 1 day after the end of each.
Is South Wales Diagnostics Limited still trading?
South Wales Diagnostics Limited is listed as active on the Companies House register as of 1 Oct 2026. Active means it has not been dissolved or entered insolvency; it does not show whether it is currently taking on work.
What does South Wales Diagnostics Limited do?
South Wales Diagnostics Limited is registered under Maintenance and repair of motor vehicles (SIC 45200).
How old is South Wales Diagnostics Limited?
South Wales Diagnostics Limited was incorporated on 3 March 2025, 1 year ago.
What is the penalty if South Wales Diagnostics Limited files its accounts late?
Companies House charges £150 if the accounts are up to 1 month late, £375 up to 3 months, £750 up to 6 months and £1,500 after that, doubled if the previous year's accounts were also late. HMRC charges £200 for a CT600 filed a day late and another £200 at 3 months.
Official records
View South Wales Diagnostics Limited on Companies House for filed documents, officers and the full history.
Based on the Companies House register (snapshot 1 Oct 2026). Deadlines are worked out from the register and assume a standard accounting period; a change of year end or a short period moves them. This page is general information, not tax or accountancy advice.