James,
If you want to fly as PIC, the biggest obstacle to overcome will be getting a
certificate of validation from CASA for your UK licence. It used to be a simple straight foward process which could be completed in one day but they managed to turn it into a bureaucratic nightmare taking weeks. I dare you to go to the home page and look at the photo without puking
Also if you want to fly away to another airport that is security controlled ie has RPT services, you will also need an Aviation Security ID Card. Lots of discussion about them on these threads. Totally useless bits of plastic that cost the best part of $200.00. They are easier to get than say 3 years ago. I suggest you contact
Aviation ID Australia who have experience in processing cards for the overseas PPLs.
Ring around the schools at the airport you want to hire from. You will require a check ride to bring you up to speed with the local Class D and adjoining CTA proecedures.
It can be done, just takes a bit of prior planning though.
If you don't want to go through the hassle, you could just go up with an instructor.