Folks thanks again for the helpful advice.
GlasgowF - I am in London but unfortunately wouldn't be able to make it out to LHR on the 17th. A huge thanks for the offer though, I'd be really up for a spin around Vic, as below I'm not going to be based there but would imagine we will be visiting and some aerial sightseeing would be superb!
I've had a really long chat with the company and it's all looking very positive with the move penciled in for late Jan so the kids can get into schools in line with the academic year. Def going to be based in Sydney so looks like Bankstown and Camden will be getting a visit once the dust has settled. From my quick Googling it looks like it's cheaper to learn down there as well?