Bongo

I'm probably going to earn more than my tax-free allowance of £1,000 in interest for the 24/25 tax year and I've spoken to my savings bank (Tandem) who say they don't automatically inform HMRC of my interest earnings. They do, however, issue their customers Certificates of Interest at the end of each tax year and say it's for the individual to pass these on to HMRC. What is the means by which I inform HMRC using one of these certificates so they can collect the correct tax? Thanks.