Welcome to the forum SW and to Sydney when you are up here.
Yes, your mail is correct and Ginza is very good. There are plenty of reviews for most of the ginza girls so let your finger do the walking and enjoy!
But no, ginza is not the only high class Asian brothels in Sydney . You should check out 5 Star as well and they also have lots of reviews and photos of their girls posted here.
Have fun!
Cheers