If you have a mortgage it might be worth paying off.
£20k in an ISA. There are many savings accounts that offer good returns too but you need to be careful if you do not want the returns to be taxable.
If you do that, there will be little left of £50k or "above" unless the "above" is another £50k.
Also, given your age, what is your State Pension forecast? If you are deficient, or might be, in entitlement you can buy extra years to max it out. Does not need to be done immediately but something to keep tabs on.