I came across this photo of a cut-down S1 racer in the September 1982 issue of Exhaust Notes (Vintage MCC of Victoria). I assume it was taken some time in the period 1978-1982 by Dave Dumble.
The bike looks much the same these days, but some history of the bike recorded in 1982 by Dave Dumble might be of interest:
"I first saw the bike at an exhibition in Adelaide in 1978. It was owned then by Alf Tofts, but it has changed hands several times since then, and is now owned by Mick Matterson... All I know is that it was adapted for racing by Bluey Stewart of Gawler [just north of Adelaide]..."
I had a quick look in the papers, but although Len Stewart was a crack SA speedway rider, I doubt he and Bluey are one in the same person. Perhaps Eric knows more.
Leon