Try going to the area where they check in things like violins, and other larger items. They invariably get loaded last, and consequently wherever you arrive the large item is the first off, along with your other luggage…
I have the 61(2) number logged as the number to call QF from overseas, which we had to do a couple of years ago when trying to get back from Italy and had problems with our booking.
Check the metro routes. There is a display near the exit from the terminals which shows all the info you need. It is an excellent system, and you can buy a multiple pass for the period you are there….
Though thanks to the female DSGT who heard of the incident on her radio, and being close by, took the appropriate action which likely saved more lives...