I sent the photo to the Australian Museum and they identified it as a Bumpnose Trevally, Carangoides hedlandensis.
Thanks for your input, Vagabond.
Cheers Bobj. Glad it's sorted, and we all now know a bit more about small trevallies as a result.
IMHO all trevallies come under the heading of "neighbours' fish" ie passable eating that can be magnanimously given away
As you say, there are stacks of good to excellent table fish to be had from Aussie coasts.