They cant refuse to tell you who the original lender is as ultimately the dispute is between you and the lender. The debt collection company is merely working on behalf of the lender. If it ever went to court, it would be the lenders solicitor who would have to turn up.
However the debt may have been sold on, in which case its whoever its been sold on to that you want to know.
Unless its an in house debt collection department (often under different trading names) then the debt collection people are just middle men.
It can be a pain in the arse sometimes though as the different departments and agencys dont always talk to each other and you may have resolved the issue with the originator and they have failed to call off thier debt dogs.

I had that with orange when i cancelled a contract for shit service. Returned phone etc to find out months later that orange collections wanted £30 off me for an unpaid bill yet id paid the bill to the retail side of orange when i returned phone and cancelled
Originally Posted by
Iain Mac
The finance company simply have to write to DVLA explaining their interest in the vehicle and pay a fee for the current keeper details, just like a parking enforcement company. DVLA hand over the name and address of the keeper and away you go.
its not even as complicated as that. DVLA are very lax with handing out info and even offer online access for a fee for certain companies and debt collection agencys are one type of company that use such access.
Also a lot of the bigger vehicle debt collection companies use ANPR vans as they are often looking for hundreds of vehicles (especially if they also have contracts with the local council to pursue parking tickets).