Getting a mortgage in the Uk while living abroad?

Hello,
Myself and my Fiance! are both Uk citizens but are currently living and working in Australia. We would like to buy a house in the Uk for when we are ready to move back and settle, as an investment and maybe to rent out in the meantime. We are both in Full time work in Australia and are just renting a property here. Would we be able to get a mortgage in the Uk? If so what kind of mortgage would be best suited and would we end up paying high interest rates? We are first time buyers.

Any advice would be much appreciated :)

Thank you