| Name | Country | Region | |
| The Paul Elliott Consultancy (CI) Ltd | British Channel Islands | Guernsey | St. Saviour |
| Grant Thornton | British Channel Islands | Jersey | St Helier |
| The Due Diligence and Investigation Company Ltd | British Channel Islands | Jersey | St Helier |
| MIL | Spain | Malaga | 29780 Nerja |
| Walker Love | UK | Ayrshire | Kilmarnock |
| Paul Read Investigations Ltd | UK | BERKSHIRE | READING |
| T/A Wilf Hurrell Investigations | UK | Cambridgeshire | Burwell |
| Cambridge Detective Agency Ltd | UK | Cambridgeshire | Cambridge |
| Blayze Ltd | UK | Cambridgeshire | Peterborough |
| Susan Ward Investigations | UK | Derbyshire | Morley |
| VT Private Investigations | UK | East Sussex | Polegate |
| Austin-Allen | UK | East Sussex | Heathfield |
| Delton INV | UK | England | London |
| Richard Arthur Lee | UK | Essex | Chelmsford |
| Quintel Intelligence Ltd | UK | Greater London | London |
| FCRM Ltd | UK | Greater London | London |
| Eccora Ltd | UK | Greater London | London |
| Central Investigation Bureau Limited | UK | Hamsphire | Portsmouth |
| P&D Investigations Limited | UK | Hertfordshire | Welwyn Garden City |
| WM Investigation Ltd | UK | Hertfordshire | Hemel Hempstead |
| Designed Professional Management Facilities Ltd | UK | Kent | Gravesend |
| Research Associates (Paul Hawkes) | UK | London | North Kensington |
| Research Associates (Paul Hawkes) | UK | London | Marylebone |
| Research Associates (Paul Hawkes) | UK | London | Notting Hill Gate |
| Walker Love | UK | Midlothian | Edinburgh |
| Grant & McMurtrie | UK | Midlothian | Edinburgh |
| Mr Andrew | UK | Midlothian | Edinburgh |
| Pegasus Investigations Ltd | UK | Midlothian | Edinburgh |
| Mendes (Investigation Services) Ltd | UK | North Lincolnshire | Scunthorpe |
| Mr Beare | UK | Oxfordshire | Oxford |
| Enquire International Limited | UK | Perthshire | Killin |
| Walker Love | UK | Renfrewshire | Paisley |
| Independant Investigation Co | UK | Somerset | Somerton |
| Psci Merit | UK | Staffordshire | Wolverhampton |
| Grant & McMurtrie | UK | Strathclyde | Glasgow |
| Walker Love | UK | Strathclyde | Glasgow |
| Cambridge Detective Agency Ltd | UK | Suffolk | Newmarket |
| Delta Close Security and Investigations | UK | Suffolk | Ipswich |
| Euro-Tec Investigation Service | UK | Surrey | Egham |
| Hogan and Co. International | UK | Surrey | Farnham |
| De Facto International | UK | Surrey | Twickenham |
| Blayze Ltd | UK | Swansea | Swansea |
| Blayze Ltd | UK | West Glamorgan | Swansea |
| M C McNeill and Co | UK | West Lothian | Bathgate |
| Blayze Ltd | UK | Wiltshire | Swindon |
| Sure Step Investigations | United Kingdom | Gwent | Monmouth |