Jack, I agree to my mind Humbers are Humbers. But I know that there was some debate at the time of launching export models, about what they should they be called Humbers or Commers because some export models from 1954 had a Commer 4.75l engine rather than the RR B60.
There was some debate about this on:
http://groups.yahoo.com/group/HUMBER-FV1600/
A fellow countryman of yours sent me the picture of an Australian Humber affirming that it had a RR engine. But to his surprise & mine the chassis plate read:
Truck, 1 Ton 4x4 CT. Commer 1601A
Chassis No 6310061
Engine No 13658
UK Humber serials were 5 digits & engine nos 4 digits. I would be interested in the serials nos on that one youv'e got. To try & get some idea of how many there may have been.
Any chance of a bigger picture?