Ahhh, shivers. You are in a difficult position.
Competency/surgical skill-wise - and this is just going by my personal experience as a 'virgin' sleever (i.e. not previously banded) - I found Stephen Watson o.k. But don't go to him if you need a support net-work. IMHO.
From other folks experience, who chose to have more post-op support, I believe that Leon Cohen at Mercy Bariatrics is good, along with (sorry - I can't remember his name! His initials are) H.C. - he is at Murdoch.
You may also wish to check out this forum. You can open up State (Australian), or sub-sections in the various topics. There are numerous banders who have gone onto be sleeved - or who have gone onto have a gastric bypass.
Can only wish you all the best.