For airlines with a High Capacity AOC the requirement under the CAO's is for only 250hrs PIC.
I don't think the ATPL requirements change because of the AOC of your employer. Isn't 500 hours PIC required for an ATPL? and in turn isn't an ATPL required to exercise a CIR on an RPT airliner?
I thought the QF cadets did have to get 500 hours before operating in command (i.e. on a 3 man crew with the Capt off the flight deck), but it is just that some of it is ICUS.
I certainly can't be bothered looking it up, but if anyone knows the lowdown I would be interested.