Max, this is from an englishman, living in AU:
Petrol is about twice the price in the UK. However, cars are hideously expensive in Australia. You're going to live in a house about three times as large as what you had in the UK (and it will most likely be full detached), no matter what your income bracket Roads are far larger, but in general, the driving skill is way worse. In this country, it is possible to watch a car, and by its brand and "body language" figure out the nationality / class of person driving it. Crime is no worse than the UK, guns are rarely heard of, though it is the fashion in the cities for psychopaths to kill innocent bystanders by punching them in the face, with them dying after they hit the concrete. Sport is great, if you like it. Pub culture is completely different. Forget going to the pub for a social drink on a weekday. Either you're going for binge drinking or you're not going (this is in cities). If you value your pub as a meeting place, don't come here - it's not the same.
etc etc