It may be easier but I resent, and I mean REALLY resent losing even a couple of quid of interest to the bloody treasury. If you have the financial willpower, put 20% away each month into a high (relatively speaking) interest savings account. Not always easy to do I know.
Is it only 20%? I thought it was 30% you had to give the tax man
I find 20% covers it once you factor in the personal allowance, occasionally I've had to find a few extra sheckles, but not much, occasionally I have too much and I take a holiday
Although I don't actually work that much any more, if you are really putting in the hours and filling up the coffers you might need a bit more.
Alternatively, and I did this until the bloke retired, I met an accountant who did my books for years and who's payment was a good spanking every couple of months. The arrangement worked out quite well