most likely you have to give your bank a copy of your house insurance and that will indicate that it is rented - if you have advised the insurer. From that the Bank will ascertain that the property is rented. Also, if you change your address for postal purposes for the bank, they will see that it is different to the address of the loan and draw the conclusion that it is rented, or at least investigate. In my opininion you are better off coming clean. dishonesty usually catches up with the dishonest, and particularly with something as long-dated as a mortgage.