Good advice from Marko regarding the HR.
You will be required to drive the tourist bus for the Bungles pickups before the flights. You used to need an F or T endorsement on a WA licence also. I had a T (regional taxi) licence however I don't think it's required anymore as the bus is not for hire or reward but a complimentary pickup for the flights. Most of the buses you can drive on a standard D/L as they are 12 seaters however one of Alligators buses did require a HR when I was there.