Disclosing disputes when selling property

I have a tenanted property that I am thinking of selling in the medium term future. I understand I need to disclose any disputes or potential disputes during the legal process.

I have an owner of a property adjacent to mine complaining about noise from my tenants. He seems very annoyed and there have been lengthy emails back and forth between me and him about it. Basically I believe a lot of what he says (but not all) is well within normal noise occurence given its in a block of flats. He has told me, quite rudely, to get sound proofing installed and to check the floors etc. I have told him its purely a tenant noise issue and nothing to do with floors. As far as I know nothing has been reported to council/police but the building management is aware.

Wondering, when it comes time to sell (which may be a while yet), what should I disclose exaclty, if anything at all? Simply that there was noise complaints about my tenants (which I imagine a buyer would ignore given its purely a tenant issue)? Or would I need to disclose more including having been told to check floors and insulate etc?

Wondering at this stage whether to communicate with him or just ignroe him completely as he is pressurising me to check floors and insulate etc.