| Name | Company Number | Date Appointed | Rating |
|---|---|---|---|
| AB RHEAD & ASSOCIATES LIMITED | 06325873 | 14/08/2015 | Dissolved |
| ALWAY ASSOCIATES (LONDON) LIMITED | 03591627 | 14/08/2015 | Dissolved |
| C-IN-A LIMITED | 02251685 | 14/08/2015 | Dissolved |
| L.R.R. HOLDINGS LIMITED | 05859313 | 14/08/2015 | Dissolved |
| THE COSTAIN CHARITABLE FOUNDATION | 09062685 | 29/05/2014 | Dissolved |
| Name | Company Number | Date Appointed | Date Resigned | Rating |
|---|---|---|---|---|
| BRISTOL WATER PLC | 02662226 | 01/01/2017 | 19/06/2018 | Amber |
| BRUNSWICK INFRASTRUCTURE SERVICES LIMITED | 05934479 | 14/08/2015 | 01/09/2020 | Not Trading |
| CALVERT & RUSSELL LTD. | 03393157 | 14/08/2015 | 01/09/2020 | Gold |
| CLM ENGINEERING (OVERSEAS) LIMITED | 02992285 | 01/06/2011 | 01/09/2020 | Not Trading |
| CONSTRUCTION STUDY CENTRE LIMITED | 02554091 | 14/08/2015 | 01/09/2020 | Bronze |
| COSTAIN ALCAIDESA LIMITED | 02042076 | 28/11/2019 | 01/09/2020 | Bronze |
| COSTAIN BUILDING & CIVIL ENGINEERING LIMITED | 01054232 | 01/06/2011 | 01/09/2020 | Gold |
| COSTAIN CIVIL ENGINEERING LIMITED | 02757907 | 01/06/2011 | 01/09/2020 | Amber |
| COSTAIN CONSTRUCTION LIMITED | 00563270 | 07/05/2019 | 01/09/2020 | Not Trading |
| COSTAIN ENGINEERING & CONSTRUCTION (OVERSEAS) LIMITED | 02440830 | 01/06/2011 | 01/09/2020 | Gold |
| COSTAIN ENGINEERING & CONSTRUCTION LIMITED | 02440829 | 08/04/2013 | 01/09/2020 | Gold |
| COSTAIN INTEGRATED SERVICES LIMITED | 01890057 | 14/08/2015 | 01/09/2020 | Amber |
| COSTAIN INTEGRATED TECHNOLOGY SOLUTIONS LIMITED | 01439838 | 05/07/2016 | 01/09/2020 | Gold |
| COSTAIN LIMITED | 00610201 | 10/07/2008 | 01/09/2020 | Silver |
| COSTAIN MANAGEMENT DESIGN LIMITED | 01599349 | 01/06/2011 | 01/09/2020 | Not Trading |
| COSTAIN OIL, GAS & PROCESS (OVERSEAS) LIMITED | 00583789 | 07/05/2019 | 01/09/2020 | Not Trading |
| COSTAIN OIL, GAS & PROCESS LIMITED | 00786418 | 31/03/2020 | 01/09/2020 | One Red Flag |
| COSTAIN PROCESS CONSTRUCTION LIMITED | 00590330 | 01/06/2011 | 01/09/2020 | Not Trading |
| LYSANDER SERVICES LIMITED | 00766914 | 30/08/2013 | 01/09/2020 | Bronze |
| PROMANEX (CIVILS & INDUSTRIAL SERVICES) LIMITED | 02224393 | 31/03/2020 | 01/09/2020 | Not Trading |
| PROMANEX (CONSTRUCTION & MAINTENANCE SERVICES) LIMITED | 03548978 | 31/03/2020 | 01/09/2020 | Not Trading |
| PROMANEX (TOTAL FM & ENVIRONMENTAL SERVICES) LIMITED | 03230494 | 31/03/2020 | 01/09/2020 | Bronze |
| PROMANEX GROUP HOLDINGS LIMITED | 05933523 | 31/03/2020 | 01/09/2020 | Dissolved |
| PROMANEX GROUP LIMITED | 03895753 | 31/03/2020 | 01/09/2020 | Dissolved |
| RG BIDCO LIMITED | 07652992 | 14/08/2015 | 01/09/2020 | Dissolved |
| RHEAD GROUP HOLDINGS LIMITED | 07652990 | 14/08/2015 | 01/09/2020 | Dissolved |
| RHEAD HOLDINGS LIMITED | 07076869 | 14/08/2015 | 01/09/2020 | Dissolved |
| WESTMINSTER PLANT CO. LIMITED | 00552140 | 07/05/2019 | 01/09/2020 | Not Trading |