DeeDee80, I suggest you ring the bank and ask how much you would have to pay monthly to reduce the term to 25 years. Once they give you the amount word your letter like so:
Please change my monthly direct debit from €X,XXX (old payment) to €X,XXX (new payment) per month. I wish the additional €XXX to be taken from the outstanding capital amount and the term reduced accordingly.
From my telephone conversation with your office I understand that this will reduce my term by approximately 10 years.
Please reply by letter outlining the reduction in term, confirming the new payment and confirming the new clearance date for the mortgage.