I retired in 2023 and have some modest annuities in place.
In February this year, I had a letter from HMRC saying that I owed then £410 in unpaid tax, which surprised me as the annuity providers according to thier P.60s appear to be taking tax off my annuities at source.
I contacted HMRC, eventually had to pay up the £410 and the lad I spoke to did some resetting of tax percentages on the gbiggeset annuity.
So fine I thought, all well until I've just had a further demand for £1,140 in unpaid tax about nine months after the first one and my tax code has changed twice in six months. 
I'm going through all my accounts, income, annuity income and things just don't seem to add up.
I will be contacting HMRC asking to explain what is going on, but can anyone shed any light as to what may be happening please - ?