- Companies
- Electricians
- Leeds
- Mayfly Hydronics Ltd
Mayfly Hydronics Ltd
- Company number
- 12881716
- Incorporated
- 15 Sep 20206 years trading
- Registered office
- 71 Tong Way, Leeds, LS12 5NB
- Nature of business
- Electrical installation; Plumbing, heat and air-conditioning installation; Other specialised construction activities n.e.c.
Mayfly Hydronics Ltd is a 6-year-old private limited company registered in Leeds, company number 12881716, one of 478 electrical contractors in Leeds. Its next accounts are due at Companies House on 30 April 2027, and the CT600 for the period to 31 July 2026 is due at HMRC on 31 July 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 unchanged on the year before, at -£2,518.
- Net assets rose in 0 of 4 year-on-year comparisons on record.
- Current assets of £95 against £2,613 owed within a year: 0.0 times cover.
- 2 employees on average during the year.
- Balance sheets on record for 5 years, 2021 to 2025.
Net assets by year
| Year end | Net assets | Cash | Current assets | Owed within a year | Employees |
|---|---|---|---|---|---|
| 31 Jul 2025 | -£2,518 | £95 | £2,613 | 2 | |
| 31 Jul 2024 | -£2,518 | £228 | £2,746 | 2 | |
| 31 Jul 2023 | -£1,595 | £380 | £1,975 | 2 | |
| 31 Jul 2022 | £2 | £2 | 2 | ||
| 30 Sep 2021 | £2 | £2 | 2 |
Where Mayfly Hydronics Ltd is registered
The registered office is in Leeds (LS12), in the Leeds local authority area, Yorkshire and The Humber. Show LS12 5NB on a map.
Other trade companies in LS12
- Ndka Investment LimitedMotor traders
- Jaw Groundworks LimitedLandscapers and gardeners
- Ivaniel Cleaning LimitedCleaning companies
- Mo Motorz LtdMotor traders
- M&A Sparkle LtdCleaning companies
- Afaaks International LtdProperty developers
- Gurmehar Motors LtdMotor traders
- Douglas Plumbing & Heating LtdPlumbers and heating engineers
What happens if Mayfly Hydronics 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 30 April 2027.
| Companies House | Accounts delivered | Penalty |
|---|---|---|
| Up to 1 month late | 1 May 2027 to 31 May 2027 | £150 |
| 1 to 3 months late | 1 Jun 2027 to 31 Jul 2027 | £375 |
| 3 to 6 months late | 1 Aug 2027 to 31 Oct 2027 | £750 |
| More than 6 months late | From 1 Nov 2027 | £1,500 |
Penalties double if the accounts were also late the year before.
| HMRC (CT600) | From | Penalty |
|---|---|---|
| 1 day late | 1 Aug 2027 | £200 |
| 3 months late | 31 Oct 2027 | another £200 |
| 6 months late | 31 Jan 2028 | HMRC estimates the tax and adds 10% of the unpaid tax |
| 12 months late | 31 Jul 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
- 12881716
- Status
- Active
- Company type
- Private limited company
- Incorporated
- 15 September 2020 (6 years ago)
- Registered office
- 71 Tong Way, Leeds, LS12 5NB
- Nature of business
- Electrical installation (SIC 43210)
Plumbing, heat and air-conditioning installation (SIC 43220)
Other specialised construction activities n.e.c. (SIC 43999) - Year end
- 31 July (accounting reference date)
- Accounts type
- Micro-entity
- Last accounts made up to
- 31 July 2025
- Last confirmation statement
- 9 February 2026
- Previous names
- Mayfly Renewables Ltd (until 10 Feb 2026)
The Boiler Store Ltd (until 17 Aug 2022)
Filing notes for electrical contractors
Electrical contracting companies are often a director plus a van and tools. Most fall within the micro-entity rules, so the accounts filed at Companies House are short, and the CT600 carries the tax detail.
Similar companies in Leeds
Other active electrical contractors registered in Leeds.
- MB Design & Production Ltd2021
- MC Systems Ltd2022
- Meb Electrical York Ltd2024
- Meson Electrical Services Limited2006
- MF Refurbishments Ltd2025
- Mfav Ltd2019
- MKD Electrical Ltd2024
- MKD Maintenance Ltd2025
All electrical contractors in Leeds · All trades in Leeds · Electricians across the UK
Frequently asked questions
When are Mayfly Hydronics Ltd's accounts due?
Mayfly Hydronics Ltd's next accounts are due at Companies House by 30 April 2027 (in 200 days), covering the period to 31 July 2026.
When is Mayfly Hydronics Ltd's CT600 due?
The CT600 for the period to 31 July 2026 is due at HMRC by 31 July 2027, 12 months after the period end. The corporation tax itself is payable earlier, by 1 May 2027.
Is Mayfly Hydronics Ltd still trading?
Mayfly Hydronics 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 Mayfly Hydronics Ltd do?
Mayfly Hydronics Ltd is registered under Electrical installation (SIC 43210); Plumbing, heat and air-conditioning installation (SIC 43220); Other specialised construction activities n.e.c. (SIC 43999).
How old is Mayfly Hydronics Ltd?
Mayfly Hydronics Ltd was incorporated on 15 September 2020, 6 years ago.
What is the penalty if Mayfly Hydronics 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 Mayfly Hydronics 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.