Information Supplied by Neil Cairns
Note that there were blocks of unused numbers between the models, so 125 M.G.s and 16 Rileys were never made! The chassis number is on a plate on the battery side inner wing, also stamped there, and on later cars a plate screwed to the nearside rear dash, up under the bonnet hinge. Body number (or commision number,) is on the radiator panel, and on some cars up under the offside inner wing. Only early cars had the number actually stamped into the offside wing by the battery. Good security would lead you to stamp it into the metal yourself........ as the plate is only held on by two little screws.( RHS2 was the Riley 1.5 Mk2.)
Chassis numbering system:
Many people read the 'S' as a '5', and the dash '/' as a '1' on their register forms. On late cars the chassis number is followed by the letter 'M', this just indicates the car was made at the 'MORRIS' factory at Cowley, not the 'Austin' factory at Longbridge.