Probably no help, but I saw a S/A frame at a swappie this morning, but as I've no need for one didn't get a price or other details.... (he also had a rigid M21).
Which leads me to a question;
I'm not sure if it was a early frame or for a single because something I noticed the other night in the '54-'57 twins (A7/10)Parts list I have, is the swing arm frames in the drawing have the oil pump curve
...and comparing that to the singles (B31/33) frame, the only difference I could see in the B31/3 Spares list was the steering lock lug on the singles one....
This frame had that lug, but also the pump curve had been welded in..
So the question is; What is/are the differences between an early and late swing arm frame ?? (Apart from the obvious ID prefix)
Disclaimer:did this on the phone- half price drinks at the pub
(2-4-1)..>two for one<