Dianna,
Perhaps a rethink about the statement 'except outside of the bombing of Darwin in WW2....'. Broome? Sydney? Various other places bombed repeatedly across Northern Australia in WW2? Besides, I seem to remember the National Flag wasn't actually officially proclaimed until the 1950s, although it existed from just after Federation.
Of course, Australians, particularly since the latter part of WW1, have always fought as a National entity, responsible ultimately to the Australian Government, rather than being spread as individual 'reinforcements' within other nation's armies. Even the RAAF personnel in the UK in WW2, although mixed with other British Commonwealth nationalities, were there by agreement, and were still responsible to RAAF command and Australian government control.
Mike C