I did this a while ago, turned up at HQ CASA in Mascot (Sydney airport) with license, log book and about $100AUD (and a smile, remember they are a CAA..).
More recently VETFLYER from these pages has been there so could give more in depth commentary on how big the smile (or dollars pile) need to be...
h-r
NB, hint, sort out the place you are hiring from from the UK before going so they can help with the process and advise on any local procedures. Enjoy.