Using SSIA funds to pay off mortgage

Hi
My SSIA matures later this year and i was planning to use the money to pay off some of my mortgage
My mortage is part fixed and part variable over 25 years

When my SSIA matures, im right that i can use the funds to reduce my mortgage?

That will mean that my monthly repayments (currently around € 1200) will go down but the mortgage term will still remain (25 years) - right?
Thanks

If your monthly payments increase, you will pay off the mortgage before the original term ends. Inform your lender that you want all additional contributions to go towards capital element of the variable portion of your mortgage (you may not be able to make additional contributions on the fixed element). To work out how many years you will take off the term, plug the figures into .

When the fixed term ends, change to a tracker rate (or variable if you cannot change to a tracker) and increase the payments.

When you pay extra off your mortgage you can either ask the lender to reduce payments and not the term or keep payments the same and reduce the term.
You should then pay anything extra you can afford off the variable part of your mortgage.
Check if you can get a tracker rate for your mortgage.