Hi All,
I only just saw this post, but I can identify whats going on with the trials BSA/ Ariel
The frame is a replica Ariel HT5, the trials model which was made famous by a certain SM
Ariel only made 400-450 of these bikes of which several thousand remain
I own an original 1957 one bought as a bare frame and a 5 gallon bucket of parts
I paid £27(?) for the kit in 1979, Many years later I found the original engine bottom end for it
John