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- Mainstream Fleet Limited
Company profile · Plumbers and heating engineers
Mainstream Fleet Limited
Mainstream Fleet Limited is a 29-year-old private limited company registered in London, company number 03365607, one of 2,972 plumbing and heating companies in London. Its next accounts are due at Companies House on 30 June 2027, and the CT600 for the period to 30 September 2026 is due at HMRC on 30 September 2027.
Key dates
Worked out from the year end and filing history on the Companies House register.
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Financial snapshot, 2025
From the balance sheet at 30 September 2025, as filed at Companies House.
Mainstream Fleet Limited over the years
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 £124K (+6.8%) on the year before, to £1.9M.
- Net assets rose in 7 of 9 year-on-year comparisons on record.
- Current assets of £2.1M against £967K owed within a year: 2.1 times cover.
- No employees reported for the latest year (directors are often not counted as employees).
- 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 |
|---|---|---|---|---|---|
| 30 Sep 2025 | £1.9M | £642K | £2.1M | £967K | 0 |
| 30 Sep 2024 | £1.8M | £620K | £1.9M | £1M | 38 |
| 30 Sep 2023 | £2M | £1.6M | £2.8M | £1.4M | 34 |
| 30 Sep 2022 | £1.8M | £2.1M | £3M | £1.8M | 36 |
| 30 Sep 2021 | £1.7M | £1.9M | £2.9M | £1.8M | 32 |
| 30 Sep 2020 | £1.1M | £1.7M | £2.8M | £2.1M | 28 |
| 30 Sep 2019 | £564K | £520K | £1.4M | £1.3M | 32 |
| 30 Sep 2018 | £418K | £954K | £1.3M | £1.5M | |
| 30 Sep 2017 | £515K | £1M | £1.2M | £1.3M | |
| 30 Sep 2016 | £364K | £966K | £1.4M | £1.2M |
Where Mainstream Fleet Limited is registered
The registered office is in London (N18), in the Enfield local authority area, London. Show N18 3QT on a map.
Other trade companies in N18
- General Fixers LtdInstallers
- Bin Store Cleaning Services LtdCleaning companies
- Vio Lettings Maintenance LtdBuilders
- MG Cars Bod Shop LtdMechanics and garages
- Critter Control Services UK LtdCleaning companies
- Jes Property Maintenance LtdRoofers
- Fanextract LtdPlumbers and heating engineers
- Lucian Aurelian Avram LtdCleaning companies
Also registered at this address
2 other companies use the same registered office as Mainstream Fleet Limited.
- Cox Auto & Commercials (London) LimitedMechanics and garages
- Kinectid LtdCivil engineering
What happens if Mainstream Fleet 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 June 2027.
| Companies House | Accounts delivered | Penalty |
|---|---|---|
| Up to 1 month late | 1 Jul 2027 to 31 Jul 2027 | £150 |
| 1 to 3 months late | 1 Aug 2027 to 30 Sep 2027 | £375 |
| 3 to 6 months late | 1 Oct 2027 to 31 Dec 2027 | £750 |
| More than 6 months late | From 1 Jan 2028 | £1,500 |
Penalties double if the accounts were also late the year before.
| HMRC (CT600) | From | Penalty |
|---|---|---|
| 1 day late | 1 Oct 2027 | £200 |
| 3 months late | 30 Dec 2027 | another £200 |
| 6 months late | 30 Mar 2028 | HMRC estimates the tax and adds 10% of the unpaid tax |
| 12 months late | 30 Sep 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
- 03365607
- Status
- Active
- Company type
- Private limited company
- Incorporated
- 6 May 1997 (29 years ago)
- Registered office
- Unit 15, Anthony Way, London, N18 3QT
- Nature of business
- Plumbing, heat and air-conditioning installation (SIC 43220)
Maintenance and repair of motor vehicles (SIC 45200) - Year end
- 30 September (accounting reference date)
- Accounts type
- Total exemption (full)
- Last accounts made up to
- 30 September 2025
- Last confirmation statement
- 22 September 2025
- Charges (mortgages)
- 0 outstanding of 6 registered
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.
- Maintain Loundon Limited2022
- Maintenance R Us Limited2024
- Maintracts Services Limited2001
- Maintrade Enterprises Limited2003
- Maison Lagrene Ltd2026
- Majestic Distribution++ Limited2026
- Mamoss Group Limited2025
- Managed Control Services Limited2010
All plumbing and heating companies in London · All trades in London · Plumbers and heating engineers across the UK
Frequently asked questions
When are Mainstream Fleet Limited's accounts due?
Mainstream Fleet Limited's next accounts are due at Companies House by 30 June 2027 (in 261 days), covering the period to 30 September 2026.
When is Mainstream Fleet Limited's CT600 due?
The CT600 for the period to 30 September 2026 is due at HMRC by 30 September 2027, 12 months after the period end. The corporation tax itself is payable earlier, by 1 July 2027.
Is Mainstream Fleet Limited still trading?
Mainstream Fleet Limited is listed as active on the Companies House register (checked 12 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 Mainstream Fleet Limited do?
Mainstream Fleet Limited is registered under Plumbing, heat and air-conditioning installation (SIC 43220); Maintenance and repair of motor vehicles (SIC 45200).
How old is Mainstream Fleet Limited?
Mainstream Fleet Limited was incorporated on 6 May 1997, 29 years ago.
What is the penalty if Mainstream Fleet 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 Mainstream Fleet Limited on Companies House for filed documents, officers and the full history.
Based on the Companies House register (snapshot 1 Oct 2026, rechecked 12 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.