Don't do an annuity. Put it in a SIPP, then: Do a drawdown plan - which with new legislation should become even more attractive. You can take 25% tax free cash. Use that to buy CASH ISAs with 5 year fixed rate bonds every year (layering) Excess cash into stocks ISA - Gilts funds (just like an annuity would invest) When the 25% runs out, take as aggresively as possible from the remaining pot and keep doing the same.
I see a great advantage in not doing an annuity is that you don't need life insurance, because if you die, the pot is passed on.
Governments like annuities because they don't like inherited wealth (makes for non-working 40/50 year olds). They would rather feed the bonuses of the life insurance/annuity companies' execs.
I am convinced you will extract more from the SIPP pot this way than handing it over for an annuity. I'd love to hear any arguments to the contrary.