So sorry to hear of your loss Joe. However, I agree with CliveV that I doubt that anything can be done.
Next time you go and buy a van take heed of what CliveV has said.
Ask pertinent question. Look at the van log book and take the name and address for checking (before parting with any cash). CHRIS are very helpful. They cannot answer questions as such, but if you couch your questions in such a way that the only response if Yes or No they are very helpful.
If the details on the log book are different from the address of sale ask for the telephone number of the owner so you can talk with them.
We looked at a caravan and wasn't too happy with the seller who said he was a dealer, but only sold a few vans yearly for a 'mate'! We took details of the owner (who did not live at the sellers address) and had a ride out (150 mile round trip) to find out about the van. Nobody home, of course! However, we put a note through the door and asked them to telephone us.
Amazingly they did and we were given all the relevant details. Still not happy so walked away.
We had several follow-up calls from the 'seller' who seemed to be having difficulty getting it off his land!!! I wonder why?