Hello, 602!
I'm very interested in old motorcycles and am currently rebuilding a 1956 BSA B31. I also ride an A10. I used to own an Airportable Landrover (lightweight) I loved it, but glad I don't run it now, not with fuel costing what it does!
Sorry I haven't got a duggie for you to measure up, but if you contact your nearest vintage motorcycle club section someone will know will have one and will probably let you check theirs out.
The Vintage Motor Cycle Club Limited
say's that the south wales section meets every other Monday at 7.30pm
Venue The Llanharry Working Mens Club , Llanharry, Nr Pontyclun, CF72 9HS
Hope thats been of some help.
Rob