| CALDWELL | — | — | — | Open → |
| CAMAK DEVELOPMENTS LTD | — | — | — | Open → |
| CAMAK DEVELOPMENTS LTD | — | — | — | Open → |
| CAMAK DEVELOPMENTS LTD | — | — | — | Open → |
| Camberwell Construction | Goole | — | — | Open → |
| Cambridge City Council | Cambridge | — | 01223 457111 | Open → |
| Cambridge Fire & Rescue Service | Peterborough | — | 01733 353220 | Open → |
| Cambridgeshire Fire & Rescue Service | Cambridge | — | — | Open → |
| Cambridgeshire Fire & Rescue Service | Huntingdon | — | — | Open → |
| CAMERON | — | — | — | Open → |
| Canada Joinery & Building Ltd | Bradford | stefkershaw502@gmail.com | — | Open → |
| Cannock Chase Council | Cannock, Staffs. | buildingcontrol@cannockchasedc.gov.uk | 01543 462621 | Open → |
| Cannock Community Fire Station | Cannock | can.enquiries@staffordshirefire.gov.uk | 01785 898060 | Open → |
| CAPEY | — | — | — | Open → |
| Cara Algar | York | — | — | Open → |
| CARDIE | — | — | — | Open → |
| Cardiff Council | Cardiff | buildingcontrol@cardiff.gov.uk | 029 2233 0383 | Open → |
| Cardiff Fire & Rescue Service | Cardiff | — | 01443 232534 | Open → |
| Cardiff Unitary Council | Cardiff | — | 029 2087 1363/1377/1153 | Open → |
| CARINA MILBURN | — | — | — | Open → |
| CARL AND FLORA BROOK | — | — | — | Open → |
| Carl Sanderson Design & Build | York | carl@carlsdb.co.uk | — | Open → |
| Carla & Chris Rouse | Leeds | carlajenna@hotmail.com / chris@rouseelec.co.uk | — | Open → |
| Carley Longden | Selby | — | — | Open → |
| CARLEY SUCH | — | — | — | Open → |