It's showing as SORNed on the DVLA website, so could well be legit, but I'd prefer one that had been used a bit, or at least had an MOT!
The vehicle details for K20 OJB are:
Date of Liability 01 07 2011 Date of First Registration 14 03 2005 Year of Manufacture 2005 Cylinder Capacity (cc) 4601CC CO2 Emissions 314g/Km Fuel Type Petrol Export Marker Not Applicable Vehicle Status SORN Not Due Vehicle Colour GREY Vehicle Type Approval M1