Sponsorship

If it is genuine sponsorship in exchange for advertising for your company, then it can be entered 100% in your accounts. Because it is actually publicity in the form of sponsorship. But then you will normally receive a document from the party you are sponsoring, won't you?

You can use that document for your accounts. Try to explain why it is sponsorship that you are already seeing publicity (publicity because then it can be included 100% in your accounts). For example, include some documentation to support the fact that it is publicity (I am assuming here that this is the case :))