Something about that bike bothered me from the day I firs saw the photographs of it
Now it has come back
That looks very much like Don Nolans old M20.
From memory that went to his brother Max after he died and Max would be getting on by now as well.
Don wanted girders and because he was getting on a bit and the body had sufferred from years of motorcycle racing back in the day he also wanted some rear end springing .
His shoulders were quite bad thus the deluxe forks with the rubber mounted handle bars
Down side was he had not ridden since having children and the ride from Lidcome to Homebush ( about 4 miles ) was too much and he had to get MArk to ride the bike home while I drove him back.

Don't think I ever saw it again as he decided to do some thing with his round tank that he never managed to finish
A really good bloke & keen BSA enthusiast .