| 0026R-474 | U1725 | MINISTRY OF DEFENCE AIR DOMESTIC R FERENCE NUMBER USE ONLY |
| 28S11543 | U1725 | MINISTRY OF DEFENCE AIR DOMESTIC R FERENCE NUMBER USE ONLY |
| BO 727 | K0207 | HALE HAMILTON (VALVES) LIMITED |
| A32 | K7766 | BRITISH STANDARDS INSTITUTION |
| A32-C44 | K7766 | BRITISH STANDARDS INSTITUTION |
| A32C46 | K7766 | BRITISH STANDARDS INSTITUTION |
| C46 | K7766 | BRITISH STANDARDS INSTITUTION |