I’ve given this some thoughtIf you want W3W details for private properties just go on the W3W website and click on the property. Or go on Google maps and get coordinates as well as a nice aerial picture of the farm layout. OS maps show nearly all farm names which can be located via a grid reference (and have done for decades). Type the farm name and postcode into Google and you'll get owner details and more often than not a phone number. Use these details for further searches to see livestock market results etc which tell you what the farm is producing.
You may have gripes about RT, but them knowing your W3W address shouldn't be one of them.
That said, I'd suggest getting a W3W address from a phone isn't consistently accurate enough to locate 1 door 10m from another.
They can have the w3w detail but will have to meet my traceability requirements,
shouldn't be a problem for them really, just some paperwork they will need to provide!
And to be honest knowing they can do all of the above without even visiting th3 site makes the w3w part pretty pointless anyway