Hi - I have been checking the info that GMAC gave me for an interest only mortgage, on reading through their tariff booklet and Mortgage Guide 2000, for Interest Rates it says the following:
"The interest rate charged will be based on "LIBOR" plus an additional amount (a "margin") e.g.3% over the Libor rate. This means that if LIBOR were at 7%, the interest rate would be 10%. The margin applied will depend on the type of scheme you are taking and your personal and financial circumstances and this will be set out in your Mortgage Offer."
OK - I notice that little bit about your circumstances, which sounds like "we will hit you with an enhanced rate if you have any adverse credit" - lol, then says:
"To help you understand how a change in the interest rate might affect your monthly payments, a typical example is given below assuming a 3 month LIBOR rate of 7.56% on a mortgage loan attracting interest of 3%, giving a total charging rate of 10.56%.
EXAMPLE: Based on a residential, interest only mortgage loan of £50,295 (Initial mortgage loan of £50,000 with a £295 arrangement fee added on a property valued at £75,000 repayable at the end of a 25 year term. Included in the calculation of the total amount payable and APR are: Arrangement fee £295, T.T. fee£30, Non block Insurance fee of £40.00, Valuation fee £220, Legal fees £350, Redemption Admin fee £155 payable at the end of the 25 year mortgage loan term. 300 gross monthly payments of £442.60. Total amount payable £183,905.00. The APR is 11.3% assuming that the 3 month LIBOR remains at 7.56% throughout the 25 year term.
For each 1% change in the charging rate, the gross monthly payment would change by £41.91p."
Hope this is helpful.