Hi Bevan,
Brisbane has some nice waters around it but if you want anything deep it would have to be boat based. There's plenty of spearfishers around Brissy but not that many pure freedivers. Haico Aldering lives up there though and i'm sure he'd be keen on getting a dive buddy. Try the forum on these websites:
www.ozfreediving.com
www.spearfishing.com.au
www.spearfishing.net.au
www.extremespearfishing.com.au
Good luck, and see you in Brissy in a couple of years (my wife's from Brisbane so we're settling there when we get home from London).
Cheers,
Ben
