Chris,
Airworks involvement ended some time in the early/mid '90s when Bristow Helicopters became the new owners of AST.
As a Flying School AST shut down around early '96.
(The Engineering School has continued as a part of Perth College.)
Flying training has continued there since under various owners, but very, very small-scale compared with the hey-day of AST, just flying club training and only two or so aeroplanes for any M/E IR training.