Condition Lever,
My understanding (from the press articles) was that an A330 operating Honolulu-to-Sydney diverted into Avalon after it was figured out that it would miss the YSSY curfew. The pax were then accommodated and later moved to Sydney using JQ A320 equipment, which meant taking an A320 off domestic rotations, causing scheduling ripples on the domestic network.
What is unsaid in the press, is that at some stage, as the A330 was scheduled to operate into Sydney, presumably it would've been scheduled to subsequently operate out of Sydney again, so it (the A330) would've had to have been positioned back to Sydney from Avalon. So my original query stands.