G'day geenhorn,
The 1976 reference here is in relation to phippH's machine with the tractor styling. Your machine is an 'earlier' example of a yellow HD8. It's got the earlier style rear mudguards. There a a couple of modifications in the IPC that I have that might help identify barnfind as being pre or post 1973. I think you have a copy of the IPC? We can chew this over with the help of a few photos- it would be an interesting exercise
Cheers,