Hi,
You are correct. If your combine UK bank / building soceity interest, NS&I interest exceeds £10,000, then you are still required to complete a self assessment tax return. You can also check
whether you still need a tax return at:
Check if you need to send a Self Assessment tax return
If a tax return is not appropriate, but we are expecting one from you, you should contact our self assesment helpline on 0300 200 3310 or contact our webchat facility at:
Contact HMRC
and confirm a tax return is not required.
Thank you.