Morgage free or not

Mmnd

Hello

Hoping to sell up and become mortgage free in the next six months
we are very lucky that we have decent equity in our property and will be able to stay in our local area although will be taking on a big project
we are tied into our mortgage until end of 2025 with an interest rate of 1.5% and a mortgage of £420k with an early redemption fee of £20k
when sold we will have approximately £650k in equity
the mortgage is portable so my question is, would I be best to just pay off the mortgage completely and take the penalty
or port the mortgage and use the equity to pay the mortgage and the allowable 10% off each year and keep the rest in high interest savings until the mortgage is renewed?
we would love to stay where we are but lockdown decimated our business and put us in debt to make ends meet
im stressing about what the repayments would be when we have to remortgage and just working to pay the mortgage at the moment
once this is out of our hair we may be able to start living and go on the occasional holiday again without the panic attacks