Bank says it doesn't report interest to HMRC

HMRC recalculated the tax due on my savings for the year ending April 2024. I'm a basic rate taxpayer who received a bonus payment that reduced my tax-free interest allowance from £1,000 to £500. I wanted to settle the underpayment in tax when I realised that one of the banks I use has not reported the interest earned in the same year. The bank is registered in the UK, however many people in this forum and on similar platforms elsewhere online have reported the same issue while using the same bank. I spoke with two HMRC representatives who advised me that the bank is expected to report the interest due, then I spoke with the bank who confirmed it's their decision not to send any details of interest earned by UK taxpayers. I need to understand if this is common practice, and whether and how HMRC would find out about the missing amount, as I'm certain the bank will be filing statutory reports for various tax reasons. I don't want to report the missing amount by myself just yet because it's unclear if the bank may decide to report the same amount at a later point in time. I don't want any duplication to occur and I don't want to have to clear up the confusion around it with either HMRC or the bank.

Hi,
While banks and building socities are no longer responsible for ensuring that any tax due on interest is collected at source and sent to us, they do still have
to send us confirmation of this interest to allow us to collect any tax due through your tax code - otherwise, they're passing this task on to their customers.
If your bank or building society is adamant that they will not be sending us confirmation of your interest, please contact us by webchat, phone or post via
Income Tax: general enquiries -
we can update your record with your interest amount, and review if any contact with your bank or building society is needed.
Thank you.