We had a 'webuyanycar.com' office open up on the supermarket car park across from us. I ended up having some signs done for the Showroom windows and have bought quite a few over the past year, most have been crackers. I take V5, copy of drivers licence and a utility bill, plus all payments have to be made direct to the registered keepers bank account, or Finance company direct if needed. I now always check on the Vehicle information site first to ensure the V5 I have is current, just in case of a log book loan that hasn't been picked up on.
The webuyanycar office over the road closed a few months ago, not just had as much traffic since, but still get the odd one or two.