Well interestingly I called the AA office in HK and upon selecting English (instead of Cantonese or Mandarin) my call was routed to their Fiji call centre who had an issue with me using an Australian card for the ex-HKG fare. But they said that it would be an 'exception' and allowed me to use it charging USD50 reservation fee instead of the USD25 originally quoted.

I'll wait to see what happens but if there is an issue does anyone know how to call straight through to the Hong Kong office? It increasingly seems that the HKD900 fare difference booking with QF might have been easier just to cough up considering it could all be done in one phone call.