Wineboy,
You are right the police BK is not a dedicated SAR/EMS machine that is only because of funding and staffing levels.
The reason that the Air Wing didn't go to Lancelin to perform the rescue is that the winch is U/S. Not because it was beyond there capability.
For w_ocker the RAAF machine is actually a Canadian Helicopter S76, on contract to provide SAR coverage for the RAAF pilots.
The BK is the helicopter operated by WA Police.