What are your other financial circumstances, how much do you have in savings otherwise and in what form (ISAs etc)? What is your pension situation, do you have a workplace pension or private pension or both and are you already making additional contributions? Any major financial expenses on the horizon, any plans to move? Any other debt (secured or unsecured?). Is your mortgage currently fixed rate, for how long if so and what's the interest rate?
MN in general is really obsessed with paying off the mortgage as early as possible, but in general I treat it as a low priority. Yes mortgage is debt but even in these days of higher interest rates you usually earn more in interest from investing elsewhere that you save by putting it against your mortgage. Mortgages (on your primary residence) are in general a secure and cheap form of borrowing and IMO not comparable to other forms of debt like credit cards and loans. Also by using the money to overpay the mortgage it then becomes illiquid as it's essential increasing the equity in your home, and you'd have to sell or remortgage to access that capital should you need it.
My plan, assuming your mortgage is currently 5% or lower (things would change if more) would be:
-Keep at least 12 months essential living expenses in an accessible account
-Pay off any high interest debt inc car finance if possible
-Make additional pensions contributions through your workplace pension or a private pension, up to the maximum tax deductible threshold.
-Invest the maximum (£20k if you don't already have an ISA opened this tax year) into a stocks and shares ISA in a low-medium performance managed fund, aiming for ~5% performance
-Consider junior ISAs for any children
-Consider a 3 or 5 fixed term bond again aiming for at least 5%
Only after this would I think about paying down the mortgage (and make sure you are reducing the capital amount/term not the monthly payment or it's pointless).