Tim,(posted 8489 days ago)I don't know the case law, but I am trying to find out for you. Meanwhile, have you tried the various legal databases? (UK Law, casebase, etc). Most of them have links to this site (eg casebase in linked in the "Repossession - your legal rights" section), so that's how you could have come across it.
To be honest, in the scenario you are describing I would have thought that the Data Protection Commissioner would have a legitimate interest. A lender ought to use basic cross-checking between systems to ensure that its processing of data is correct. If you could get yourself an Assessment on these grounds in your favour, you would have made your point. A DPC's Assessment costs you nothing; and you also alert the DPC to these problems and so help others.
all best