I was in a similar situation 5 years ago, in September 2019. Though it wasn’t classed as redundancy, I got a £50k pay off to leave, and took my pension at the same time.
IIRC, as you say, the first £30k was tax free. I was then taxed at my usual rate @20% (£43k salary). I even got a £3.5k tax refund a couple of months later – though that might have been my employers incompetence calculating my final payslip.
I was never taxed at the higher rate of 40%, but that might have been because I didn’t draw any pension for around 9 months, thus keeping my annual income under the threshold