You may want to contact Doug Menadue of Bespoke Gems. He is located in Sydney. I am an overseas customer from Europe and Doug cut three stones for me. His cutting is fabulous. He has cut many stones for PS-ers.
I've heard good things about Seda Gems (I believe they are in AUS). I've never purchased from them, but have spent some time on their site and found them responsive when I had questions.
But IMHO Doug Menaude is the best option. I adore his cutting and his prices are very reasonable.