Hi Ian,
Thanks for the reply, much appreciated.
Ok, well that kind of makes sense I guess! I've been doing some similar original research myself from photographs of cars that appear to be unaltered, to see if there is any correlation between FE / F / Body / Commission / Car Numbers, & VIN's etc.
What I think I've discovered is that as the bodies were built by Pressed Steel Fisher (PSF) Division, any records of the numbering system & sequence would have been most likely created and held by them, rather than the main arm of BMC, BL, Rover etc. I may take a trip to Gaydon this year to see if they hold any records in their archive to verify this.
As you say though, there does seem to be some approximate match, although it tends to be inconsistent, but gets you into the right ball-park.
Weirdly, my own cars VIN actually contains all the same numbers as the Body Number, but in a slightly different order!
It would be interesting to hear from somebody who used to work at PSF, who could help by imparting some of that valuable knowledge to us. Is there anybody out there?
Cheers,
Steve.