- Companies
- Machinery repair and installation
- London
- Mainstay Sys Ltd
Mainstay Sys Ltd
- Company number
- 15726726
- Incorporated
- 17 May 20242 years trading
- Registered office
- 3RD Floor, 86-90, Paul Street, London, England, EC2A 4NE
- Nature of business
- Repair and maintenance of ships and boats; Agents involved in the sale of machinery, industrial equipment, ships and aircraft
Mainstay Sys Ltd is a 2-year-old private limited company registered in London, company number 15726726, one of 1,743 machinery repair and installation companies in London. Its next accounts are due at Companies House on 28 February 2027, and the CT600 for the period to 31 May 2026 is due at HMRC on 31 May 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 31 May 2025, as filed at Companies House.
Where Mainstay Sys Ltd is registered
The registered office is in London (EC2A), in the Hackney local authority area, London. Show EC2A 4NE on a map.
Other trade companies in EC2A
- Simlan Management LtdCleaning companies
- Renova Secure LtdBuilders
- Auraglasspartitions LtdGlaziers
- A2D Professional Cleaning LtdCleaning companies
- Matson Co. LtdProperty developers
- Paint Hub LimitedMechanics and garages
- SJK Construction & Management LtdBuilders
- Cenlora Cleaning Group LtdCleaning companies
Shared registered office
1,581 companies on our pages use this registered office address. An address shared this widely is usually an accountant's office or a company formation agent's service address, not where the business trades from.
What happens if Mainstay Sys Ltd 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 28 February 2027.
| Companies House | Accounts delivered | Penalty |
|---|---|---|
| Up to 1 month late | 1 Mar 2027 to 31 Mar 2027 | £150 |
| 1 to 3 months late | 1 Apr 2027 to 31 May 2027 | £375 |
| 3 to 6 months late | 1 Jun 2027 to 31 Aug 2027 | £750 |
| More than 6 months late | From 1 Sep 2027 | £1,500 |
Penalties double if the accounts were also late the year before.
| HMRC (CT600) | From | Penalty |
|---|---|---|
| 1 day late | 1 Jun 2027 | £200 |
| 3 months late | 31 Aug 2027 | another £200 |
| 6 months late | 30 Nov 2027 | HMRC estimates the tax and adds 10% of the unpaid tax |
| 12 months late | 31 May 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
- 15726726
- Status
- Active
- Company type
- Private limited company
- Incorporated
- 17 May 2024 (2 years ago)
- Registered office
- 3RD Floor, 86-90, Paul Street, London, England, EC2A 4NE
- Nature of business
- Repair and maintenance of ships and boats (SIC 33150)
Agents involved in the sale of machinery, industrial equipment, ships and aircraft (SIC 46140) - Year end
- 31 May (accounting reference date)
- Accounts type
- Micro-entity
- Last accounts made up to
- 31 May 2025
- Last confirmation statement
- 16 May 2026
Filing notes for machinery repair and installation companies
Machinery repair and installation companies often carry parts stock and specialist tools, and many work on contracts that span the year end.
Similar companies in London
Other active machinery repair and installation companies registered in London.
- Maintenance Aviation Service Ltd2025
- Maintenance Group UK Limited2026
- Maintenet Ltd2017
- Maks Power Ltd2023
- Mambo Electrics Limited2025
- Manchester Foreign Trade Co Ltd2019
- Mans Systems Ltd2023
- Manzoor Enterprise Ltd2022
All machinery repair and installation companies in London · All trades in London · Machinery repair and installation across the UK
Frequently asked questions
When are Mainstay Sys Ltd's accounts due?
Mainstay Sys Ltd's next accounts are due at Companies House by 28 February 2027 (in 138 days), covering the period to 31 May 2026.
When is Mainstay Sys Ltd's CT600 due?
The CT600 for the period to 31 May 2026 is due at HMRC by 31 May 2027, 12 months after the period end. The corporation tax itself is payable earlier, by 1 March 2027.
Is Mainstay Sys Ltd still trading?
Mainstay Sys Ltd 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 Mainstay Sys Ltd do?
Mainstay Sys Ltd is registered under Repair and maintenance of ships and boats (SIC 33150); Agents involved in the sale of machinery, industrial equipment, ships and aircraft (SIC 46140).
How old is Mainstay Sys Ltd?
Mainstay Sys Ltd was incorporated on 17 May 2024, 2 years ago.
What is the penalty if Mainstay Sys Ltd 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 Mainstay Sys Ltd 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.