| Company | Site | Proficient | Accredited | |
ADM Milling Ltd |
Avonmouth |  | | | |
Corby | | | | |
Edinburgh | | | | |
Knottingley | | | | |
Liverpool | | | | |
Seaforth | | | | |
Tilbury | | |
| Allied Mills |
Belfast | | | | |
Manchester | | | | |
Tilbury | | |
| Jas Bowmans & Sons Ltd |
Goole | | | | |
Hitchin | | |
| E B Bradshaw & Sons Ltd |
Driffield | | |
| Carrs Flour Mills Ltd | Siloth | | |
| Robert Hutchison & Co. Ltd | Kirkaldy | |
|
| Heygates Ltd |
Bugbrooke | | | | |
Downham Market | | | | |
Tring | | |
| Kerry Milling |
Gainsborough | | |
| W H Marriage & Sons Ltd |
Chelmsford | | |
| Wm Nelstrop & Co Ltd | Stockport | | |
| Rank Hovis Ltd |
Andover | | | | |
Barry | | | | |
Glasgow | | | | |
Manchester | | | | |
Rotherham | | | | |
Selby | | | | |
Southampton | | | | |
Wellingborough |
|
|
| Ripon Select Foods Ltd |
Ripon | | |
| Ryvita Company Ltd |
Poole | | |
| Smiths Flour Mills |
Holbeach | | | | |
Langley | | | | |
Worksop | | |
| G R Wright & Sons Ltd |
Enfield | | |
|
