There's another very important but unclear zone which I find a lot of people don't appreciate with UK pensions, which is:
- above ~1m - pension starts to lose its TFLS advantage over ISA due to the max TFLS cap (you may still get net tax advantage from income tax relief and salary sacrifice)
- above ~1.6m - while it this depends on your withdrawal rate, the principle is that there is no advantage to having an amount in a pension where you are paying 40% marginal rate income tax on it vs just paying that up front and putting it into an ISA. Assuming a 4% WR this number comes to (67026 * 25) = £1.676m. If you draw a 5% WR then the number is 1.34m
Also, this doesn't mean that your pension needs to reach those numbers by pension access age - the likelihood is that with continual growth of the invested pot, even while you are drawing down from it they are likely to reach those numbers at some point even as you are drawing from them.
So, there's a zone starting at about £1m where the pension's advantage over ISAs is gradually reduced... first through the capping of the TFLS amount, and then naturally by the income tax bands, where, realistically, if you are trending above ~£1.5m, or are otherwise certain to be paying higher rate income tax on withdrawals (or inheritance tax on death) the pensions offer no further advantage and indeed becomes a drawback due to its inflexibility.