Hi Lisa,
I think you have got it exactly right and your realistic that you may 'ping pong pom', but having taken the gamble initially to make the move at least in 10-15 years you won't regret anything.
I have been in Aussie now 3 years and it's still not 'home' and I don't think it ever will be.
Everytime I go back to the UK I love it. I'm 30 and have just moved to Sydney from Perth and think the same as you, (good job, good money, nice flat etc etc but something is missing.
After spending New Years Eve alone in my local pub, I know how tough it is.
If you wana catch up and have a good moan drop us a line.
Ps.... That new English/ Traditional Chippy in Bondi is well worth a visit.