nibbio.
It should be one approved by the manufacturer.
I don't believe Pratt & Whitney either "approve" a course for pilots or have an "approved" course for pilots. Also CASA no longer have a BGT course as a pre requisite to a turbine aircraft endorsement.
I suggest you call Pratts and ask for a Field Service Engineer:
Pratt & Whitney Canada (A'Asia) Pty Ltd
Phone: (07) 3268 0000
30 Industry Crt
Eagle Farm QLD 4009
Many years ago they used to produce excellent free pilot literature, including turbine engine theory and handling notes for each class of engine. No idea if that is still the case.