| Name | Country | Region | |
| Radar Detectives | Italy | Italy | Livorno |
| Walker Love | UK | Aberdeenshire | Aberdeen |
| Walker Love | UK | Ayrshire | Kilmarnock |
| Black Isle Services | UK | Berkshire | Slough |
| Paul Read Investigations Ltd | UK | BERKSHIRE | READING |
| Standby Investigation | UK | Buckinghamshire | High Wycombe |
| Blayze Ltd | UK | Cambridgeshire | Peterborough |
| Susan Ward Investigations | UK | Derbyshire | Morley |
| Richard Arthur Lee | UK | Essex | Chelmsford |
| Eccora Ltd | UK | Greater London | London |
| Total Fleet Management | UK | Hampshire | Petersfield |
| Central Investigation Bureau Limited | UK | Hamsphire | Portsmouth |
| P&D Investigations Limited | UK | Hertfordshire | Welwyn Garden City |
| Bunting and Baker | UK | Lincolnshire | Boston |
| Research Associates (Paul Hawkes) | UK | London | North Kensington |
| Research Associates (Paul Hawkes) | UK | London | Notting Hill Gate |
| M Private Investigations Ltd | UK | Middlesex | Hampton Hill |
| Walker Love | UK | Midlothian | Edinburgh |
| Grant & McMurtrie | UK | Midlothian | Edinburgh |
| Mr Andrew | UK | Midlothian | Edinburgh |
| Pegasus Investigations Ltd | UK | Midlothian | Edinburgh |
| Mr Beare | UK | Oxfordshire | Oxford |
| Walker Love | UK | Renfrewshire | Paisley |
| Independant Investigation Co | UK | Somerset | Somerton |
| JBB Investigations | UK | South Yorkshire | Rotherham |
| Psci Merit | UK | Staffordshire | Wolverhampton |
| Grant & McMurtrie | UK | Strathclyde | Glasgow |
| Walker Love | UK | Strathclyde | Glasgow |
| Blayze Ltd | UK | Swansea | Swansea |
| Security Risk Management Ltd | UK | Tyne and Wear | Newcastle Upon Tyne |
| Blayze Ltd | UK | West Glamorgan | Swansea |
| M C McNeill and Co | UK | West Lothian | Bathgate |
| Blayze Ltd | UK | Wiltshire | Swindon |