Problem is when you put the reg. no into the DVLA web site under the date of liability you normaly see the tax or Sorn expiry date. However for the car in question it gives the date 20/04/2006, so appears that it has not been taxed/sorned since then
That's what I was thinking, however the seller has his name as the current owner in the V5 (not a company) but if he is a dealer he is not disclosing that fact to me and is selling as a private ad.