So... I thought it would be easy to identify (why do I always think that?).
I did a Google search and there are photos like this on US websites were someone says they're cricket nymphs. But... I can't find an Aussie picture of a reputable website to make me feel happy with that definition.
In the back of my mind is something telling me that the massively long antennae are a key feature... but blowed if I can remember what of!
And I'm not sure those legs look like jumping legs. Wish I took better photos - but it was 1 am or something!
But it's not a termite (phew!), or a cockroach, so it must be something like a cricket or grasshopper or something like that, surely.
I'm getting some more pictures of things I know :) It's demoralising not to know what it is!