It's Bill Nicholson at the 1947 TT on a works BSA developement bike...It's a rigid frame with a swinging arm conversion, works front brake, oiltank and other features..Notably it has the all aluminium version of the B29/B30 engine which ultimately became the 350cc 1949 ZB32 Gold Star after further developement...BSA made only 12 sets of these alloy top ends..I know one still exists in New Zealand...Ian
