Firko, I remember travelling to Mt Kembla with my father and other Port Pirie MCC club members for the 1967 Australian Championships and Matt dominated, winning the 250 and 350 events as well as 2nd in the 500 and Unlimited on the Husky. I think he was #15 that day (I don't know what his regular number was).
Wasn't it mid 67 when Matt was supplied the Huskies
Ray Fisher won the Unlimited and 500cc on a Matchless Metisse, but I thought he rode under #33 all the time
??
Laurie Alderton was also in the mix in the big bore events.
So, I suspect 1967.
The highlight of the trip for me was being taken to Chapel Street in the Cross at age 15. Have never looked back