Ivermectin is generally considered safe for rabbits. Yes it's possible for a negative reaction to occur, particularly with Dutch rabbit genetics and Blue Eyed White, but it's rare it happens with most rabbits when it's dosed correctly. If your rabbit isn't those breeds, I wouldn't worry too much about using it.
I've used the injectable ivermectin, but just give it orally. Dose is 0.4mg/kg for at least 3 treatments 10-14 days apart. If the solution is 1% (10mg/ml), the amount given is 0.04ml/kg, less than 1/10th an ml/cc, a very very small amount. This is my own calculation, it's best to check with your vet and/or double check all calculations on your own.
(Mite treatment info)
Medirabbit: ear mites
If you still would rather try Revolution/Stronghold- selamectin (dosed at 18mg/kg for rabbits), the US and UK both require a prescription, but I don't think Australia does. There are some sites that ship worldwide. There's some discussion on this chat thread below, about others ordering internationally. But I can't say anything to how legit or reliable the two sites mentioned in the thread are, so that's something you'll want to research yourself.
Reddit discussion
https://www.vgr1.com/revolution/