This is what I have relative to the Spitfire:
Inspection Stamps related to the Spitfire:
6.S or 6S over xx in circle for Vickers Armstrong Supermarine Works, Southampton
GAL 6S over xx in oval(?) for General Aircraft Ltd (indicated contracted production for Supermarine Division)
CBAF over xx in circle for Castle Bromwich Aircraft Factory
VACB over xx in circle for Castle Bromwich Aircraft Factory
VACH over xx in circle for Vickers Aircraft, Chester
VABL over xx in circle for Vickers Aircraft, Blackpool
WA over xx in circle for Westland
COA over xx in circle for Cunliffe Owen Aircraft, Southampton
WBxx in circle for Westland, Brough???? or Winchester, Broadlands????
Manufacturer's marks related to the Spitfire:
ALD for Aldermaston Aerodrome (final assembly)
AST for Air Service Training, Hamble (Spit Mk V to Seafire Mk IB conversion)
COA for Cunliffe Owen Aircraft, Southampton (Spit Mk V to Seafire Mk IB conversion)
CHA for Chattis Hill Aerodrome (final assembly)
EA for Supermarine, Eastleigh Airport (final assembly)
FL for Folland, Hamble
HEA for Henley Aerodrome (final assembly)
HPA for High Post Aerodrome (final assembly)
KEA for Keevil Aerodrome, Trowbridge (final assembly of Spit Mk V, Mk VIII, etc)
PP or PPSM for Phillips & Powis, South Marston (Vickers owned from 1 April 1943, produced Spit Mk 21)
R-R or R-RH for Rolls Royce, Hucknall (Mk V to Mk IX conversion)
6.S or 6S for Vickers Armstrong Supermarine Works, Southampton
YE for Westland, Yeovil Aerodrome (Spit & Seafire production, final assembly, and repair)
??? for Heston Aircraft Co, Heston Aerodrome, Middlesex (repair of Spit and modification to PR types)
VAHPk for Vickers Armstrong, Hursley Park (I do not know if they actually manufactured parts here or not)
W.B.Ltd/CBAF for Westland, Brough???? (indicated contracted production for CBAF)
WIN for Winchester???? (do not know what was done here) or Swindon, South Marston????? (modification work, Seafire and Spit Mk 21 production)
And now WA for Westland. Do you know if the WA was used as a general stamp or for a specific site/complex?
Pobjoy Airmotors and Aircraft Ltd. was purchased by Short Brothers in 1938, maybe they used a different stamp acronym after that?