1. I'm not the person to ask about SIPPs, as I retired long enough ago for this never to have been relevant to me, apart from reading subsequently that I could do small SIPP payments each year even without relevant earnings. Everything I've read about draw-down makes it sound complicated and full of traps for the unwary. Not for me, even if it had been available!
I have to say that since I drew on a small Personal Pension Plan that I contributed to in the early 1970s, and found that my brilliantly-performing fund would only buy a pretty pitiful annuity because of the low annuity rates (they are worse still now!), I rather went off the idea of pensions altogether. The real problem I find is that the annuity market sets the rates and never gives anything away, and the government currently sets the interest rates at a really miserly level, and the annuity market therefore starts at a very low level of benefit for the pensioner, especially after the insurance company's profits.
2. Widow's pension is always calculated from the full pension that the pensioner would have received : the TFLS only reduces the employee's pension, not his widow's. The widow's pension is also incremented in the same way as the employee's pension.
3. Beware of the "3% increases" figure.
There are 2 traps here for the unwary :
a) If the reason for increasing, such as "RPI up to 3%" comes in with a lower figure, you get the lower figure (naturally); but if inflation is, say, 7%, you only get 3%, so you lose ground in every year when inflation is over 3%, and don't make it up when it's under 3% (unless the pension fund makes a discretionary increase - and can afford to do so!)
b) If your pension scheme was a contracted-out one, which I suspect it was, your pension payments will be in 2 parts : one that matches the government's Guaranteed Minimum Pension, and one that covers the rest.
I've found in my own case that although I certainly get the stated increases to 'the rest', I don't get any increase at the moment from the GMP part, so the overall pension doesn't go up as much as expected relative to the RPI.
All this being the case, I think you would be wise to apply the cash you receive from the firm, after keeping back enough to cover any higher-rate tax liability on the redundancy money exceeding £30,000 !, to investing for growth of income in particular.
This means avoiding the highest-paying shares and funds in favour of lower-paying ones that have more scope for growing dividends in the future. For example, Centrica and Vodaphone shares may pay a comfortingly high dividend at the moment, but the big question is 'How fast and how reliably will future dividends grow in the next 20-30 years from this source'?
Most investment commentators will accordingly try to steer you away from shares and funds yielding 5% to 8%, and towards those yielding no more than the market average.
If you can find, for example, an investment trust that yields say 3% now, but on looking at its past track record it has grown the dividend by 5% p.a. for the last 20 years, then it's a much better money-spinner than something paying 4% now but with past growth of dividends of 'only' 3% p.a.
Citywire statistics, and those on Digitallook and other websites may give you a feel for which ones are REALLY better bets.
Also, with investment trusts, you can always email the company itself and ask for stats on 'income growth on a year-by-year basis for the last 20 years, or since launch if more recent'.
Good firms will leap at the chance to help you!