No. This rule was removed several years ago, but some in QF try to tell you different. QF in Collins St seem to know the rules (or at least some of them).

Buying thru AA will be cheaper (less surcharges) as is buying in AKL, instead of Aust. Have a look a AFF and oneworld.com

If you are going to SCL a flight out Easter Island (IPC) is worth it. Interesting place to vist for 2 or 3 days

The AKL/SYD-SCL segment is very hard to get a D class seat on QF or LA. Try both and all combinations. Guys at work fly this route frequently. Often they can not buy a business class seat so they go in Y or via LAX. If you find D availibilty grab it quick and book everything esle around it. Several threads on this topic

Many people avoid LHR. Take the chunnel train BRU-LON-Paris