bought mine off ebay private seller - didnt even view it beforehand 
deposited 10k via bacs and went to pick it up a week later 
sold my old car to a dealer on the way  to pickup the Z - my last exposure thankfully 
looking back.... 
  
having said that - no issues with the private seller route 
  
initially Z views,in my experience, were just flipped auction cars - you may as well goto auctions yourself and take the risk rather than paying over £1k for the privilege of a valet