Have bought a number of vehicles on eBay. Principle is to assume that the vehicle doesnt exist until proven otherwise, seller is a crook until proven otherwise (or dealer pretending to be private seller) and the car has hidden/disguised faults until proven otherwise/ Lots of clues above (use google reverse search to check whether the photos have ‘borrowed’ from another car, HPI or similar before you view then check the VIN & engines nos versus V5C etc etc.
Would never sell through eBay again, I use Autotrader for the past 3 cars and motorhome and moped. Seems attract less tyre kickers and would take (-£1000) less than you have advertised types.
There are great cars out there, but it really is buyer beware!