i would say your ok, on the mota website they seem to say they will extend for as long as necessary due to the wait times etc and theres no mention of mileage limits. i would just give them a ring and ask but i dont think you will have a problem. unless your desperate to change, apart from the new focus the ap’s at the moment are rediculous so unless there was a compelling reason to change i would extend and see what happens.
extend for the full 2 years, you can then jump in at any time during that 2 years if something comes up at a reasonable price.