.....I forgot to mention...
Hi Trogdor,
Something I forgot to mention (and the most important bit too) is the Australian tax aspect. What I am about to say will be applicable to you if the Australian govt deems you to be "an Australian non-resident for tax purposes".
Basically, and you may know this already, normally as an Australian resident you can claim the property expenses (interest, body corp, PM fees, council rates, etc) against the rental income and when the former is greater than the later you investment is operating at a 'loss' and you get the negative gearing situation.
However, as a non-resident, and presumably receiving a UK salary taxed by the UK govt, you have no other Australian income to offset your property losses against. This being the case, those property losses accumulate indefinately year after year whilst you remain an Australian non-resident. When you come back to Australia, those accumulated "tax credits" can be used to offset against a rental surplus, capital gains on sale, or to offset australian taxable income. And there is no rule to say that you can only claim those losses in the first tax year of your return to Australia. You just claim them until they have all been used up, however long that takes. So theoretically, you could be in a situation where you pay no Australian income tax for X number of years when you get back, depending on how much you have accumulated in losses. Sounds too good to be true, but its absolutely brilliant.
Its one of the key advantages of buying property as a non-resident.
I suggest you see an Australian accountant in London if you haven't done so already.
Cheers,
Justin.