Repay or remortgage advice

Hi looking for post sequestration mortgage advice. I was discharged in 2013 and had a voluntary repocession carried out on my then home accomodation. I was however able to retain a rental property after buying out the ORs interest. This has now become my home property. My question is, should I change my current property mortgage from a interest only buy to let to a repayment with approx 10 years to go at approx £ 650 pcm. Or would I be better keeping the current low interest only payments and saving a deposit up for when I am 6 yrs post BR and getting fresh mortgage and possibly re letting out my old rental property to assist with the payments, which would be over a max of 17yrs. Any advice greatly appreciated as I am at a loss what to do for best. Thanks.