You need to work out how much you need to achieve the lifestyle you'd like for this part of your life.
Those sums don't sound like anywhere near enough to retire now tbh, and £12k redundancy is peanuts. But it depends on your actual and forecast outgoings - eg do you run a car, is your mortgage paid off? Could you do some other sort of work to make up the shortfall?
It's always easier to find another job when you're still in one, but be careful with that because it might invalidate redundancy if you accept a job before signing the redundancy.
If you stayed, would you have spare money to invest in an extra pension or ISAs?
Also, check if your employer supplies free or subsidised advice from an independent financial planner? They would be able to help you work out what your options are. Failing that, do they offer counselling as an employee benefit and could you access a life counsellor if so?
An IFA will really only give financial advice and one of the tricky things is working out how you want to spend this latter part of life - this is something I have struggled with.
Work is more than just money - it's also status, social contact etc.
There's an American podcast called Retirement Answers Man which has helped me with this.
Forget about the divorce decisions - I bet you're better off without him and that's priceless.
Take your time to consider carefully - this is a big life decision - good luck.