Tax on bank interest

I have a joint account and work full time. My partner is self-employed and fills out an annual self-assessment so any bank interest over £1000 he declares on his SA. However, how would I let HMRC know about the 50% of bank interest I receive?

Hi Andy Legge,
Your banks and building societies will automatically inform us of any untaxed interest received after the end of the tax year.
You can read more here
Tax on savings interest
Thank you.