Four months ago I bought a used Volkswagen Transporter from my local approved dealer. About a month ago I discovered that it had been repaired prior to me purchasing it. I assume the dealer did it as they told me it had been a lease van for a year, so it had a few minor imperfections.

The salesman told me they didn't sell on crashed vans, but this vehicle has clearly had a serious accident. The paint is not present on the underside of the wheel arch, just white primer, and rust is just starting to appear. The driver's side door also rubs on the front wing.

The dealer isn't being very useful - what what are my rights?