As far as I know (ie, my contract says)..... that you will return to your original position. So if you are a FA in SYD SH then you go back to being a FA in SYD SH after 2 years.
Again, the contract is for 2 years and all the same relocation allowances are paid. We've just had some Aussie crew transfer up under exactly the same conditions as the first transferee's (is that a word!?).
I'm not sure when we're taking more Aussie crew, but would suggest talking to your CCTM or getting in contact with the base manager up in London. He's very approachable.