Before you pay off the mortgage consider carefully what if any likely borrowings you might need in say next 2/3 yrs e.g a car loan,house improvement loan. Any such borrowing will cost a great deal more than your mortgage Tracker rate.
Consider keeping a nest egg for rainy days in a high interest paying on demand account, the interest will offset that what you are paying and you have the flexibility and security of having cash available in an emergency scenario.
By all means pay off a chunk of the mortgage but keep some for reasons set out above.