- Companies
- Plumbers and heating engineers
- London
- Diamond Plumb Limited
Diamond Plumb Limited
- Company number
- 05105998
- Incorporated
- 19 Apr 200422 years trading
- Registered office
- 28 Wimbledon Park Road, London, SW18 1LT
- Nature of business
- Plumbing, heat and air-conditioning installation; Technical testing and analysis
Diamond Plumb Limited is a 22-year-old private limited company registered in London, company number 05105998, one of 2,972 plumbing and heating companies in London. Its next accounts are due at Companies House on 30 November 2026, and the CT600 for the period to 28 February 2026 is due at HMRC on 28 February 2027.
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.
- Net assets up £11K (+3.7%) on the year before, to £315K.
- Net assets rose in 8 of 9 year-on-year comparisons on record.
- Current assets of £171K against £17K owed within a year: 9.8 times cover.
- 1 employee on average during the year.
- Balance sheets on record for 10 years, 2016 to 2025.
Net assets by year
| Year end | Net assets | Cash | Current assets | Owed within a year | Employees |
|---|---|---|---|---|---|
| 28 Feb 2025 | £315K | £27K | £171K | £17K | 1 |
| 29 Feb 2024 | £304K | £13K | £146K | £13K | 1 |
| 28 Feb 2023 | £323K | £43K | £179K | £25K | 1 |
| 28 Feb 2022 | £299K | £179K | £48K | 2 | |
| 28 Feb 2021 | £282K | £167K | £59K | 1 | |
| 29 Feb 2020 | £269K | £147K | £21K | 1 | |
| 28 Feb 2019 | £244K | £217K | £25K | ||
| 28 Feb 2018 | £224K | £198K | £22K | ||
| 28 Feb 2017 | £190K | £178K | £32K | ||
| 29 Feb 2016 | £173K | £60K | £165K | £37K |
Where Diamond Plumb Limited is registered
The registered office is in London (SW18), in the Wandsworth local authority area, London. Show SW18 1LT on a map.
Other trade companies in SW18
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- Nexlink Technologies LtdElectricians
- Straightedge Builders LtdProperty developers
- Parsons Green Re Design & Build LimitedProperty developers
- Home Appliances Repair LimitedRepair services
- 34 & 34A Lambrook Terrace Freehold LtdProperty developers
- 30 Thorndean LtdProperty developers
- Fircroft Group LimitedProperty developers
What happens if Diamond Plumb 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 30 November 2026.
| Companies House | Accounts delivered | Penalty |
|---|---|---|
| Up to 1 month late | 1 Dec 2026 to 31 Dec 2026 | £150 |
| 1 to 3 months late | 1 Jan 2027 to 28 Feb 2027 | £375 |
| 3 to 6 months late | 1 Mar 2027 to 31 May 2027 | £750 |
| More than 6 months late | From 1 Jun 2027 | £1,500 |
Penalties double if the accounts were also late the year before.
| HMRC (CT600) | From | Penalty |
|---|---|---|
| 1 day late | 1 Mar 2027 | £200 |
| 3 months late | 28 May 2027 | another £200 |
| 6 months late | 28 Aug 2027 | HMRC estimates the tax and adds 10% of the unpaid tax |
| 12 months late | 28 Feb 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
- 05105998
- Status
- Active
- Company type
- Private limited company
- Incorporated
- 19 April 2004 (22 years ago)
- Registered office
- 28 Wimbledon Park Road, London, SW18 1LT
- Nature of business
- Plumbing, heat and air-conditioning installation (SIC 43220)
Technical testing and analysis (SIC 71200) - Year end
- 28 February (accounting reference date)
- Accounts type
- Unaudited abridged
- Last accounts made up to
- 28 February 2025
- Last confirmation statement
- 2 August 2026
Filing notes for plumbing and heating companies
Plumbing and heating companies frequently work under CIS for main contractors and also directly for homeowners, so turnover can mix CIS and non-CIS income.
Similar companies in London
Other active plumbing and heating companies registered in London.
- Diamond Plumbers Limited2020
- Diaz Plumbing Ltd2025
- Dibfix Ltd2025
- Dida Plumbing Ltd2026
- Dilano's Construction Ltd2026
- Direct Gas Utilities Ltd2023
- Direct Leak Detection Ltd2026
- Direct Plumbing Services Limited2025
All plumbing and heating companies in London · All trades in London · Plumbers and heating engineers across the UK
Frequently asked questions
When are Diamond Plumb Limited's accounts due?
Diamond Plumb Limited's next accounts are due at Companies House by 30 November 2026 (in 48 days), covering the period to 28 February 2026.
When is Diamond Plumb Limited's CT600 due?
The CT600 for the period to 28 February 2026 is due at HMRC by 28 February 2027, 12 months after the period end. The corporation tax itself is payable earlier, by 1 December 2026.
Is Diamond Plumb Limited still trading?
Diamond Plumb 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 Plumb Limited do?
Diamond Plumb Limited is registered under Plumbing, heat and air-conditioning installation (SIC 43220); Technical testing and analysis (SIC 71200).
How old is Diamond Plumb Limited?
Diamond Plumb Limited was incorporated on 19 April 2004, 22 years ago.
What is the penalty if Diamond Plumb 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 Plumb 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.