Thanks to the responders, I have looked at all the regs, and am still no closer to understanding. Any reference to charter or commercial ops is not applicable to me. I'm done with professional aviation, flying now is just for me, just for fun, just for personal satisfaction........well more fun than spending squillions to chase a golf ball round a course.
On my last trip to the States, I rode a few times in a friends Mustang. What a blast, so easy to fly. Subjectively, one third of the workload compared to a Chieftain., or anything with pistons for that matter.
CASA/Oz seems determined to put people off personal aviation. It's completely different in the US, C210 owner wants to upgrade to a CJ4, sure why would't you not want to, "we can train you to operate it safely.....no problem". The whole industry is encouraging, aim high and reach the top of your potential. Nothing like that here.
Maybe I should just by a boat instead.