Thanks Graham - it is our only UK property and primary residence. As we haven't bought anywhere out here in Australia I understand the rules are that you are allowed to rent it out for up to 6 years before becoming liable for capital gains tax to the ATO.
I'm hoping we can avoid it in the UK as well, having been out of the country for over 5 years, but will be seeking professional advice on this at some point before we come to sell.
Cheers
Jim