When in doubt, and in a serious situation (such as when a lender is demanding payment of an ancient unbsubtantiated 'claim', e.g.) send a copy of ther letter to the Information Commissioner (formerly the Data Protectioner Commissioner) and ask for an 'assessment'.(posted 8434 days ago)The IC will be able to guide you.
In ther meantime you could always tell the lender that you await the IC's opinion. Or not.