I'm biased. I live in Perth but the weather is great, there are clean beaches, we drive on the same side of the road. Other things come into it like if you are clever you would book a course of some kind. Now whilst this would cost you money it could entitle you to a student visa. This allows you to work for 25 hours a week and this can greatly extend your cash and hence your flying time. Check this out with a flying school as they may even be able to arrange the visa.
Cars in WA don't have to have a MOT so there are a lot of cheap run abouts available, just be careful when buying. However Jandakot even has Chalet accomodation available to rent on the airport grounds but you would have to check out how cost effective it is.
The one thing to watch out for is that you don't fall in love with the place. Did I mention that Airline Pilot is one of the high points scorers in the migration process! Oh and 700 quid sounds a bit steep for a flight to OZ.
Hope you enjoy whatever you decide on.