Medibank will cover us for the trip (20% discount on basic rate due to medical insurance status) though the ++ for existing conditions is on a per person basis, so there is a moderate plus for me and an almost 100% add on for Mrs WF. And since they have quoted the pre-existing bits, it would now be very risky to "un-insure" those bits. The call being that we would need to show that a normal person would have similar expenses / treatments when compared to our expenditures if we needed to make a claim (theoretically for accidents as well)
The real issue is that the coverage is (theoretically) required to be from home departure to home arrival, though commencing with the first flight, we have a week in Australia and the last 4 days before the last flight back to Perth are in Australia. Leading to these portions to be charged at the Asia (HKG) rate (a seriously more expensive overseas location since Australia has almost no medical calculated in).
In the end we will risk the WA road trip parts (five days out / five hours back) and state we are departing / arriving back from our son's "house" in Perth (if pushed)
Just wandering
Fred