I can't see why they would make you pay £100 to the RAC, surely this is for a vehicle inspection .
Also the sequence of owners doesn't seem right, i could see it being owned by Nissan GB, then two private owners but surely Nissan wouldn't buy a car from a private individual.
Also, i'd check the tread depths as i would of thought 18K on original tyres would be pushing it, partiularly on the rear