Which box on SA100 should I put untaxed interest income from a family loan into?

I have loaned money to my childern (formally documented and secured on their property) with interest at market rates. Where should I be declaring the untaxed interest I receive? In box 2 of Income:Untaxed UK Interest on Page TR3 of SA100? Elsewhere on the forum (link below) Admin 30 and Admin 32 seem to have given conflicting answers, with one appearing to say it should be included as peer-to-peer lending in SA101 (but P2P is defined as 'many-to-many' lending through regulated and authorised platforms) and the other saying it shoudl go into 'untaxed UK interest in Box 2 of SA100'. https://community.hmrc.gov.uk/customerforums/sa/d21dbd7f-1a81-ed11-97b2-00155d3ba57b#8833797f-1a81-ed11-81ad-6045bd0e7d7b

Hi,

This would be peer to peer lending and should be declared on the SA101.

Thank you.