Found a pic of a rack I had on the back of the '73 HQ PV.
I had the PV, wanted to transport the Suzuki to Cairns in '75, by luck saw one on the rear of another PV at a local mechanic's workshop. Can't remember what I paid, probably around around $50, perhaps $100 (was getting paid around $120 per week in those days). Rack fixed to tow ball tongue via the 50mm ball, mounted bike, was a bit wobbly, had a mate fabricate a couple of lengths of 50 x 50 angle iron, these were fixed on both sides, wobble fixed.
PS. Don't show the pic of me in '75 to the ladies, I'll probably need to fight them off. Although, as the pic was 50 years and 30kg ago, I'm probably safe now.