Your other option would be spend the $$$ and run with Virgin. I'd go with the airline I have the most status on, as Boxing Day SYD-BNE is always full on and there may be limited options for rebooking if your flight gets cancelled.
I have avoided boxing day by booking on Xmas day. If that fits your plans, you could use a mix of paid and rewards seats, and staying at or near BNE airport. QF558 at 20.35 ex SYD has 3 Y award seats available and QF540 at 1705 has 3 J award seats available. Not sure what would be available on VA.
