Ed, as far as I understand, if a VH registered aircraft is operating overseas, then it is operating under Australian Law. Same for other countries as well.
On a semi related note, if a baby were to be born on an Australian registered aircraft, then that baby is then a citizen of the country,
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I can't think of the actual Reg, but it'd be under the CAR's 1988 or CASR's 1998.
Cheers
Mick