This is how you should do it
Call the owner, tell them that before you ask them any questions you have to warn them that this converstion is being recorded and any inaccurate information will result in you taking court action to recoup any monies lost in time wasted by the vendor, it is possible to say this in a nice way, along the lines of really sorry mate, but I have had my time wasted so many times that I have to cover my back.
Then ask them to describe the car, and you will get a very true description of condition