The ability to make overpayments depends on the lender and type of product you have.
Typically, if you have a fixed rate product, the lender will have a restriction of overpaying a maximum 10% of the balance annually. If you have a Standard Variable Rate product, then there are usually no restrictions to the amount you can repay at any time.
We have access to special products giving your flexibility to make payments which exceed your 10% allowance without a penalty, as well as allowing you to clear the whole mortgage without incurring an early repayment charge. However, the lender may charge a small exit fee which is typically a few hundred pounds.