Hi Anna
Our 7 year old SWCAH daughter had her surgery when she about 3 months old. The surgery was performed at the Royal Children's Hospital in Brisbane by Dr Peter Borzi. His details are as follows:
Dr Peter Borzi, Pediatric Surgeon and Urologist, Taylor Medical Centre, 40 Annerly Road, Woolloongabba, ph: 0738463915 (across the road from Mater Children's Hospital).
He is a pediatric urologist and so only works with children, but it would be worth calling his rooms to make some enquiries about someone they may recommend. He has a lot of experience in this type of surgery and is very good, so I'm sure he would be will to assist you.
By the way, we also live on the Gold Coast, fantastic place!