You should tell them you want *all* information they hold to which you have right of access under current Data Protection law.(posted 8415 days ago)Add that you reserve the right to request further information based on the material they supply in response to this SARN or based on subsequent needs.
Add that you reserve the right to exercise your separate disclosure (AKA discovery) rights if they begin legal action against you.
Do not make them an offer. Here's why:
1. the debt is not yet proven to you 2. making an offer could be argued as you admitting to this unproven debt 3. if you haven't got the cash then you shouldn't offer cash you haven't got.
Do read the Repossession sectino of the site thoroughly - there's lots of new material that is relevant to you in there.
Good luck,
Lee