- Companies
- Plumbers and heating engineers
- Stanmore
- GJM Southern Group Ltd
GJM Southern Group Ltd
- Company number
- 09432720
- Incorporated
- 10 Feb 201511 years trading
- Registered office
- 2 Mountside, Stanmore, Middlesex, HA7 2DT
- Nature of business
- Plumbing, heat and air-conditioning installation; Other building completion and finishing; Other specialised construction activities n.e.c.; Combined facilities support activities
GJM Southern Group Ltd is a 11-year-old private limited company registered in Stanmore, company number 09432720, one of 50 plumbing and heating companies in Stanmore. Its next accounts are due at Companies House on 31 May 2027, and the CT600 for the period to 31 August 2026 is due at HMRC on 31 August 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 £902K (+41.5%) on the year before, to £3.1M.
- Net assets rose in 7 of 9 year-on-year comparisons on record.
- Current assets of £3.1M against £825K owed within a year: 3.8 times cover.
- 7 employees 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 |
|---|---|---|---|---|---|
| 31 Aug 2025 | £3.1M | £2.8M | £3.1M | £825K | 7 |
| 31 Aug 2024 | £2.2M | £1.8M | £2.5M | £800K | 7 |
| 31 Aug 2023 | £1.3M | £1.4M | £1.6M | £301K | 7 |
| 31 Aug 2022 | £813K | £515K | £919K | £116K | 4 |
| 31 Aug 2021 | £563K | £319K | £654K | £103K | 3 |
| 31 Aug 2020 | £825K | £676K | £1M | £242K | 3 |
| 31 Aug 2019 | £756K | £745K | £1M | £304K | 3 |
| 31 Aug 2018 | £72K | £22K | £147K | £82K | 3 |
| 28 Feb 2017 | -£29K | £859 | £3,078 | £34K | 2 |
| 29 Feb 2016 | £282 | £715 | £3,092 | £4,685 |
Public contracts won
GJM Southern Group Ltd has 6 public sector contract awards on record; the ones with their own published value total £581K, from 2025 to 2026. Source: Contracts Finder and Find a Tender award notices. These were matched by the company's exact name because the notice gave no company number.
Awards by year
Main buyers
- Kent County Council6 awards
| Buyer | Contract | Value | Awarded |
|---|---|---|---|
| Kent County Council | Willesborough Infant School: Roof Repair | £50K | 21 Aug 2026 |
| Kent County Council | St Marks CofE Primary School -Replacement of Failed Oil Boilers | £105K | 13 Aug 2026 |
| Kent County Council | Willesborough Infant School - Boiler replacement work a complete heating plantroom replacement, including the conversion from an oil heating system to natural gas | £113K | 29 Jun 2026 |
| Kent County Council | Ramsgate Library GSHP Replacement | £115K | 3 Feb 2026 |
| Kent County Council | Holy Trinity & St Johns Primary School - Damp work | £49K | 29 May 2025 |
| Kent County Council | Marsh Academy Air conditioning phase 1 | £148K | 10 Mar 2025 |
Where GJM Southern Group Ltd is registered
The registered office is in Stanmore (HA7), in the Harrow local authority area, London. Show HA7 2DT on a map.
Other trade companies in HA7
- Vatra Developments LtdBuilders
- Air and Waves LtdPlumbers and heating engineers
- R & R Building Services LtdFinishing trades
- Berculean BBV Ltd LtdBuilders
- Velorent LtdMotor traders
- Autex LtdMechanics and garages
- TH Motorcycles LtdMotor traders
- Ady Painting and Decorating LtdInstallers
Shared registered office
93 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 GJM Southern Group 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 31 May 2027.
| Companies House | Accounts delivered | Penalty |
|---|---|---|
| Up to 1 month late | 1 Jun 2027 to 30 Jun 2027 | £150 |
| 1 to 3 months late | 1 Jul 2027 to 31 Aug 2027 | £375 |
| 3 to 6 months late | 1 Sep 2027 to 30 Nov 2027 | £750 |
| More than 6 months late | From 1 Dec 2027 | £1,500 |
Penalties double if the accounts were also late the year before.
| HMRC (CT600) | From | Penalty |
|---|---|---|
| 1 day late | 1 Sep 2027 | £200 |
| 3 months late | 30 Nov 2027 | another £200 |
| 6 months late | 29 Feb 2028 | HMRC estimates the tax and adds 10% of the unpaid tax |
| 12 months late | 31 Aug 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
- 09432720
- Status
- Active
- Company type
- Private limited company
- Incorporated
- 10 February 2015 (11 years ago)
- Registered office
- 2 Mountside, Stanmore, Middlesex, HA7 2DT
- Nature of business
- Plumbing, heat and air-conditioning installation (SIC 43220)
Other building completion and finishing (SIC 43390)
Other specialised construction activities n.e.c. (SIC 43999)
Combined facilities support activities (SIC 81100) - Year end
- 31 August (accounting reference date)
- Accounts type
- Total exemption (full)
- Last accounts made up to
- 31 August 2025
- Last confirmation statement
- 16 July 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 Stanmore
Other active plumbing and heating companies registered in Stanmore.
- Gohil Plumbing Services Ltd2025
- H M S Heating Services Limited2023
- Hex Mechanical Services Ltd2025
- I-Ventilation Ltd2019
- Interdeco Ltd2017
- J.R.J. Heating Services Ltd2017
- JKP Services Ltd2022
- Keates Pipework Installation Limited2017
All plumbing and heating companies in Stanmore · All trades in Stanmore · Plumbers and heating engineers across the UK
Frequently asked questions
When are GJM Southern Group Ltd's accounts due?
GJM Southern Group Ltd's next accounts are due at Companies House by 31 May 2027 (in 230 days), covering the period to 31 August 2026.
When is GJM Southern Group Ltd's CT600 due?
The CT600 for the period to 31 August 2026 is due at HMRC by 31 August 2027, 12 months after the period end. The corporation tax itself is payable earlier, by 1 June 2027.
Is GJM Southern Group Ltd still trading?
GJM Southern Group 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 GJM Southern Group Ltd do?
GJM Southern Group Ltd is registered under Plumbing, heat and air-conditioning installation (SIC 43220); Other building completion and finishing (SIC 43390); Other specialised construction activities n.e.c. (SIC 43999); Combined facilities support activities (SIC 81100).
How old is GJM Southern Group Ltd?
GJM Southern Group Ltd was incorporated on 10 February 2015, 11 years ago.
Has GJM Southern Group Ltd won public sector contracts?
Yes. GJM Southern Group Ltd has 6 contract awards from public bodies on Contracts Finder and Find a Tender (those with their own published value total £581K), most recently from Kent County Council.
What is the penalty if GJM Southern Group 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 GJM Southern Group 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.