I have arranged a return trip to Perth. I leave Sydney 14th July, and return 1st August.
Spoke to Brooke next door this morning. She'll be happy to watch the house while I'm away and will even get one of the kids to feed the cats (she's allergic herself).
Both cats are a bit shy but they respond to feeding well! That's a relief. I'll be giving her a spare set of keys and contact numbers before I go, just in case. Assuming I can get the dogs looked after elsewhere, I'll probably shut up the front of the house (carpeted) and the cats can get in to the back area (lino only). They will be cat poo when I get back, but at least it'll be easier to clean.