Tax on interest with pay rise / tax band change within the tax year

Good Afternoon All, I'm researching a problem I never thought I'd have due to a "messy" house move this year. Essentially, over a period of January to July - I was in-between houses having sold and awaiting a move date. The funds from this were put into savings accounts with interest past the personal allowance on the basic rate, all of which has now stopped and is up-to-date with HMRC. (in the grand scheme of things, it's a very small amount - hundreds not thousands). However, I am likely to get a pay increase for February 2024 - which may (including the interest) take me over into the higher band. How does this affect the previous interest gained? i.e. is that all suddenly taxed at 40% and not 20%? - basically I'm trying to work out if I'm better off delaying any pay increase until the new tax year (as it would be under). Thanks all,

Hi

This wil be reviewed after the 5/4/24 to see what your level of income actually is.
If you are a higher rate taxpayer, the savings allowance will reduce to £500 and any interest above this will then be liable to 40%

Thank you