[pabloke99]

Thanks to Nickywes' inspirational idea, we have now sold to a couple that were desperate to buy our house but couldn't sell their smaller 3-bed. So we part-exchanged. We will now have a much smaller mortgage on a perfect rental property so can head to Oz without the worry of a 'white elephant' of a house back here; with the added bonus of retaining a rental investment property in the UK.
I suppose that this is straight forward anyone with a modicum of business acumen, can't believe we didn't think of this sooner.