US SS Payments And UK Tax Year

I receive my US SS pension monthly payments into my UK bank, nominally on the 3rd of every month.  This year, because of the Easter holidays, April's payment will likely arrive on the 6th - it hasn't arrived as of the 5th anyway.  That being the case, I assume it will belong to the 2021-22 UK tax year, rather than 2020-21.  Anyone confirm?

Ever since I got back to England I treated my HMRC return as having the US calendar year income co-terminus with the UK tax year.  I receive 2 US private pensions and will be receiving SS in due course. One time I did sell some stock before April 6th but reported it as being sold on April 6th to keep the calendar year in line with the HMRC year.

I would not hesitate in counting your last SS payment as being in the 20/21 tax year, or if you prefer, delaying it to the 21/22 tax year, whichever works best for you.  HMRC are pretty flexible I find.