I can understand no interest from buyers but why has there been "not even a nibble of interest" from renters? Are you demanding too high a rent or insisting on "professional tenants only, no kids, no pets, no smokers etc"? Try and get your house rented, at whatever rent you can achieve - it will be great help to you!
You should build up emergency fund to help you cope with future interest rate rises and other extra expenses. Do you have any money saved? If not, then it would be good to get interest-only extension and use the difference between full repayments and interest-only to build up the emergency fund.
Also look for ways to increase your income, even just in the short-term, e.g. part-time work. Save all extra income for the emergency fund.