Mate, there is a long time charter operator operating a Cheyenne lll here in Perth, Central Air is company name.
According to a quick search just now he is still operating, a PA-42 - 720, rego VH-BUW . It was flying out of Jandakot on 19 Nov according to an online trcking site. Try giving him a call and asking where he gets his done. Probably Airflite as someone mentioned if they are the Aust Piper Distributor. Good Luck, Cheers.