- Companies
- Builders
- Mountain Ash
- Diamond Design Interiors Building and Maintenance Limited
Diamond Design Interiors Building and Maintenance Limited
- Company number
- 14669961
- Incorporated
- 17 Feb 20233 years trading
- Registered office
- 62 Forest View, Mountain Ash, CF45 3DU
- Nature of business
- Construction of domestic buildings; Other construction installation
Diamond Design Interiors Building and Maintenance Limited is a 3-year-old private limited company registered in Mountain Ash, company number 14669961, one of 24 building contractors in Mountain Ash. Its next accounts are due at Companies House on 31 December 2027, and the CT600 for the period to 31 March 2027 is due at HMRC on 31 March 2028.
Key dates
Worked out from the year end and filing history on the Companies House register.
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Finances
From each year's balance sheet filed at Companies House. Small companies do not have to publish turnover or profit, so these are balance sheet figures.
- 3 employees on average, up from 1 the year before.
- Balance sheets on record for 3 years, 2024 to 2026.
Net assets by year
| Year end | Net assets | Cash | Current assets | Owed within a year | Employees |
|---|---|---|---|---|---|
| 31 Mar 2026 | 3 | ||||
| 31 Mar 2025 | £23K | £691 | £1,073 | 1 | |
| 31 Mar 2024 | £2,169 | £9,851 | £1,682 | 1 |
Public contracts won
Diamond Design Interiors Building and Maintenance Limited has 4 public sector contract awards on record, from 2024 to 2026. Source: Contracts Finder and Find a Tender award notices. For all of them the published figure is a shared or multi-year ceiling (a framework place, a multi-supplier award, or more than a small company could hold alone), so no value is shown. 3 of these were matched by the company's exact name because the notice gave no company number.
Awards by year
Main buyers
- Merthyr Tydfil Housing Association1 award
- Pembrokeshire County Council1 award
- Barcud Shared Services1 award
- Rhondda Cynon Taf CBC1 award
| Buyer | Contract | Value | Awarded |
|---|---|---|---|
| Merthyr Tydfil Housing Association | Merthyr Housing Maintenance Framework | Ceiling, not shown | 5 Aug 2026 |
| Pembrokeshire County Council | Minor Works Framework Agreement for Building Maintenance | Ceiling, not shown | 22 Apr 2026 |
| Barcud Shared Services | BSS24005 -Works of Adaptations | Ceiling, not shown | 2 Feb 2026 |
| Rhondda Cynon Taf CBC | Disabled Adaptations and Repairs Framework (Darf) | Ceiling, not shown | 1 Nov 2024 |
Where Diamond Design Interiors Building and Maintenance Limited is registered
The registered office is in Mountain Ash (CF45), in the Rhondda Cynon Taf local authority area, Wales. Show CF45 3DU on a map.
Other trade companies in CF45
- Pro Guard Home Improvements LtdRoofers
- Smiths Rendering & Resin LtdBuilders
- Ironrootslandscaping LimitedLandscapers and gardeners
- Lee Griffiths Contractors LimitedFinishing trades
- Theglossboss LtdCleaning companies
- Brickzen Constructions LtdInstallers
- STR Drylining LtdBuilders
- Greenvoltinfrastructure LtdCivil engineering
What happens if Diamond Design Interiors Building and Maintenance 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 31 December 2027.
| Companies House | Accounts delivered | Penalty |
|---|---|---|
| Up to 1 month late | 1 Jan 2028 to 31 Jan 2028 | £150 |
| 1 to 3 months late | 1 Feb 2028 to 31 Mar 2028 | £375 |
| 3 to 6 months late | 1 Apr 2028 to 30 Jun 2028 | £750 |
| More than 6 months late | From 1 Jul 2028 | £1,500 |
Penalties double if the accounts were also late the year before.
| HMRC (CT600) | From | Penalty |
|---|---|---|
| 1 day late | 1 Apr 2028 | £200 |
| 3 months late | 30 Jun 2028 | another £200 |
| 6 months late | 30 Sep 2028 | HMRC estimates the tax and adds 10% of the unpaid tax |
| 12 months late | 31 Mar 2029 | 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
- 14669961
- Status
- Active
- Company type
- Private limited company
- Incorporated
- 17 February 2023 (3 years ago)
- Registered office
- 62 Forest View, Mountain Ash, CF45 3DU
- Nature of business
- Construction of domestic buildings (SIC 41202)
Other construction installation (SIC 43290) - Year end
- 31 March (accounting reference date)
- Accounts type
- Micro-entity
- Last accounts made up to
- 31 March 2026
- Last confirmation statement
- 16 February 2026
Filing notes for building contractors
Building companies often run the Construction Industry Scheme as a contractor, a subcontractor or both. CIS deductions suffered during the year are set against the PAYE bill, and any unrecovered balance at the year end matters when the accounts are drawn up.
Similar companies in Mountain Ash
Other active building contractors registered in Mountain Ash.
- GSP Electricians Ltd2021
- Jiga Hertz Electrical Engineering and General Services Limited2020
- JJ Brickwork and Stonework Specialists Limited2020
- KR Windows Installations Ltd2024
- KW Groundworks Ltd2017
- Largercoast Group Ltd2022
- Orp Drylining Ltd2019
- P.L.T Construction Limited2025
All building contractors in Mountain Ash · All trades in Mountain Ash · Builders across the UK
Frequently asked questions
When are Diamond Design Interiors Building and Maintenance Limited's accounts due?
Diamond Design Interiors Building and Maintenance Limited's next accounts are due at Companies House by 31 December 2027 (in 444 days), covering the period to 31 March 2027.
When is Diamond Design Interiors Building and Maintenance Limited's CT600 due?
The CT600 for the period to 31 March 2027 is due at HMRC by 31 March 2028, 12 months after the period end. The corporation tax itself is payable earlier, by 1 January 2028.
Is Diamond Design Interiors Building and Maintenance Limited still trading?
Diamond Design Interiors Building and Maintenance 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 Diamond Design Interiors Building and Maintenance Limited do?
Diamond Design Interiors Building and Maintenance Limited is registered under Construction of domestic buildings (SIC 41202); Other construction installation (SIC 43290).
How old is Diamond Design Interiors Building and Maintenance Limited?
Diamond Design Interiors Building and Maintenance Limited was incorporated on 17 February 2023, 3 years ago.
Has Diamond Design Interiors Building and Maintenance Limited won public sector contracts?
Yes. Diamond Design Interiors Building and Maintenance Limited has 4 contract awards from public bodies on Contracts Finder and Find a Tender, most recently from Merthyr Tydfil Housing Association.
What is the penalty if Diamond Design Interiors Building and Maintenance 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 Diamond Design Interiors Building and Maintenance 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.