Does your organisation offer a free consultation with an in depednent pension advisor. I would definitely say this should be your first route. If not, consider getting an IFA - you may have to pay but this is a once in a lifetime decision. You can’t afford to get it wrong!
As has been said, up to 25% of your pension pot can be taken as a tax free lump sum but be mindful that it will reduce your actual pension payments for the rest of your life (and your widow’s pension if ever applicable). Taking the lump sum has its advantages - it can be tax efficient in that your actual pension will have a lower amount that is subject to tax and also it gives you early access to monies that can be used to pay off existing debt, purchase something or invest.
My only advice would be to be careful not to be blinded by the lump sum - the reduction is based on an actuarial calculation and for example, mine is 1:12 in that if I take the lump sum then live for 12 more years after taking the pension, I am technically out of pocket plus your lump sum is no longer able to get annual increments which your pension will.
All very personal decisions and you need an independent appraisal that gives you the options and then for you to decide which is right for you and your circumstances.