Good answer Mechanica
your reply prompted me to google Triumph T80 and I found this
website
if you look at the T80 the exhaust configuration doesn't match the photo but the forks and, particularly the slanted casing beneath the cylinder is definately right for the T80
The T100 has a similar exhaust and forks but that engine casing does not match - I wonder if it is a T80 with another exhaust on it
We know that he owned the bike just after the war - hence the lady wearing trousers - but we don't know if he bought it new or second hand - research is still being done
can anyone out there in the UK tell me when the registration was likely to have been issued