Well I'm a Kiwi, not an Aussie. A traditional Xmas dinner served about 2pm in the middle of summer is an experience. There's the thrill of cooking dinner, then spending the hottest part of the day eating it. Leftovers make for a good picnic on Boxing Day.
We discovered that one of the game food places here has wild pork hams, and I'll be checking to see if I can get one this year. That cold with perhaps a crayfish if it can be had at a good price, or some steamed green-lipped mussels would be a better alternative to the full meal.
Rumour has it that most Aussies just put some prawns on the barbie at the beach.