| Company name | Based in |
|---|---|
| Xander Projects | St Ives, Cambridgeshire, PE27 |
| Xavier Design & Build | Luton, Bedfordshire, LU2 |
| XM Installation & Services Limited | Brentwood, Essex, CM14 |
| Xpress Electrical | Weybridge, Surrey, KT13 |
| Xuvas Group Ltd | Ilford, London, IG2 7 |