Inspired by JoeIT's post - http://www.ozbargain.com.au/node/87343, I decided to try searching for cheap multi-city flights on Kayak.
Etihad seem to be extremely cheap compared to all the other airlines, and I couldn't find the same deal via the Etihad website:
KUL - LHR, Monday 24th June (via Abu Dhabi)
LHR - SYD, Thursday 18th July (via Abu Dhabi)
$1060 (708GBP) return - via eBookers
Combine this with Air Asia's current 'Chinese New Year deal' (expires 17th Feb):
SYD - KUL, Sunday 23rd June
$329 one-way
Total $1389 per person inc. taxes
I booked yesterday and managed to get myself, wife and child to the UK and back peak-season for just over $4000. Too good not to share. We have decided to stay in KL for one night as I don't trust Air Asia to get us there in time for the connecting flight which is a three hour gap but the more adventurous can give it a go.
We did a similar thing just before Christmas last year. PER-KUL return with AirAsia, then KUL-LHR, CDG-KUL with Malaysia Airlines. All up under $6000 for a family of four return during peak Christmas season.
Good find, hopefully other people will find it useful.
Does Etihad's KUL-LHR stop somewhere else in between, though?