Thanks
JohnAx,
Received your PM. ^
At this stage I will be arriving on CX from HKG (prob the one via via BKK) so that part is looking very good.
I've already booked my MEL-HKG journey using miles (The QF miles needed increase by 20% in 2½ weeks) and will be connecting directly (albeit with a 6 hour transit) to CX703 (HKG-BKK-CMB). It's an AUD 810 return HKG-CMB and I get to stay a couple of days to look around. So all is looking good.
p.s. I also checked coming from SIN/BKK to CMB rather than HKG. Turned out to be AUD190 more expensive (same flight goes HKG-BKK/SIN-CMB).