- Companies
- Civil engineering
- Harwich
- SDB Signalling Limited
SDB Signalling Limited
- Company number
- 10743346
- Incorporated
- 27 Apr 20179 years trading
- Registered office
- Flat 4, 2 Cliff Road, Flat 4, 2 Cliff Road, Harwich, Essex, CO12 3PP
- Nature of business
- Construction of railways and underground railways
SDB Signalling Limited is a 9-year-old private limited company registered in Harwich, company number 10743346, one of 12 civil engineering contractors in Harwich. Its next accounts are due at Companies House on 31 January 2027, and the CT600 for the period to 30 April 2026 is due at HMRC on 30 April 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 £5,969 (+489.7%) on the year before, to £7,188.
- Net assets rose in 5 of 7 year-on-year comparisons on record.
- Current assets of £6,444 against £4,399 owed within a year: 1.5 times cover.
- 1 employee on average during the year.
- Balance sheets on record for 8 years, 2018 to 2025.
Net assets by year
| Year end | Net assets | Cash | Current assets | Owed within a year | Employees |
|---|---|---|---|---|---|
| 30 Apr 2025 | £7,188 | £6,444 | £4,399 | 1 | |
| 30 Apr 2024 | £1,219 | £4,087 | £2,187 | 1 | |
| 30 Apr 2023 | £13K | £20K | £0 | 1 | |
| 30 Apr 2022 | £4,474 | £18K | £6,654 | 1 | |
| 30 Apr 2021 | £337 | £35K | £28K | 1 | |
| 30 Apr 2020 | £7,292 | £2,253 | £10K | 1 | |
| 30 Apr 2019 | £44 | £3,659 | £4,681 | ||
| 30 Apr 2018 | £41 | £7,299 | £8,680 |
Where SDB Signalling Limited is registered
The registered office is in Harwich (CO12), in the Tendring local authority area, East of England. Show CO12 3PP on a map.
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What happens if SDB Signalling 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 31 January 2027.
| Companies House | Accounts delivered | Penalty |
|---|---|---|
| Up to 1 month late | 1 Feb 2027 to 28 Feb 2027 | £150 |
| 1 to 3 months late | 1 Mar 2027 to 30 Apr 2027 | £375 |
| 3 to 6 months late | 1 May 2027 to 31 Jul 2027 | £750 |
| More than 6 months late | From 1 Aug 2027 | £1,500 |
Penalties double if the accounts were also late the year before.
| HMRC (CT600) | From | Penalty |
|---|---|---|
| 1 day late | 1 May 2027 | £200 |
| 3 months late | 30 Jul 2027 | another £200 |
| 6 months late | 30 Oct 2027 | HMRC estimates the tax and adds 10% of the unpaid tax |
| 12 months late | 30 Apr 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
- 10743346
- Status
- Active
- Company type
- Private limited company
- Incorporated
- 27 April 2017 (9 years ago)
- Registered office
- Flat 4, 2 Cliff Road, Flat 4, 2 Cliff Road, Harwich, Essex, CO12 3PP
- Nature of business
- Construction of railways and underground railways (SIC 42120)
- Year end
- 30 April (accounting reference date)
- Accounts type
- Micro-entity
- Last accounts made up to
- 30 April 2025
- Last confirmation statement
- 26 April 2026
Filing notes for civil engineering contractors
Civil engineering contractors usually carry plant and machinery, so capital allowances (the annual investment allowance and the main pool) do much of the work in the corporation tax computation.
Similar companies in Harwich
Other active civil engineering contractors registered in Harwich.
- Soluli Ltd2013
- T & L Surveying Limited2013
- A.Smith & Sons (Building) Limited1991
- C.R.Bayley Ltd2011
- Clifton Contracts (Harwich) Limited1988
- Dave Soar Rail Limited2015
- Dmo Rail Limited2021
- Inland Waterways Specialists Ltd2021
All civil engineering contractors in Harwich · All trades in Harwich · Civil engineering across the UK
Frequently asked questions
When are SDB Signalling Limited's accounts due?
SDB Signalling Limited's next accounts are due at Companies House by 31 January 2027 (in 110 days), covering the period to 30 April 2026.
When is SDB Signalling Limited's CT600 due?
The CT600 for the period to 30 April 2026 is due at HMRC by 30 April 2027, 12 months after the period end. The corporation tax itself is payable earlier, by 1 February 2027.
Is SDB Signalling Limited still trading?
SDB Signalling 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 SDB Signalling Limited do?
SDB Signalling Limited is registered under Construction of railways and underground railways (SIC 42120).
How old is SDB Signalling Limited?
SDB Signalling Limited was incorporated on 27 April 2017, 9 years ago.
What is the penalty if SDB Signalling 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 SDB Signalling 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.