Non coded income

I am retired and receive only an occupational pension altough I still pay higher rate tax and therefore complete a SA annually. When I check my PAYE Income Tax summary for 6 April 2023 to 5 April 2024 (ie current yax year) I see that in addition to my pension income there is several thousand in "non-coded income". The only other income I receive is from bank savings which would be declared as part of my Self Assessment return for 2023/24 - but clearly, that is not due untill next year and, anyway, I will not know the exact amounts untill the end of this financial year. Please advise how/where the amount of non-coded income comes from so that, if mecessary, I can check that it is correct? Alternatively, should I use the option offered the website to update (to £0) or remove the non-coded income amount completely since I don't recognise the figures quoted?

Hi andrew,
We would need to access your record to check what the non coded income relates to.
You can contact HMRC here:
Income Tax: general enquiries
Thank you.