All those that purchase AIP DAP and the amendment service pay for the design of RNAV approaches. I would expect that CASA would have criteria for when an AD/ALA needs an instrument approach designed for it and so the cost of that approach would be shared amongst all.
For ADs that don't meet those criteria an Approach will not be designed unless you want to pay for it. Since QES paid for the one at Atherton (no favouritism - they paid commercial rates) they get to use it.
The coroner may well ask why you elected not to pay for a safer approach to be designed - or do you only want somebody else to pay for it.