Well, LondonItalian did say that people modify XJ40s with different grilles and headlights and wheels, as is probably the case with the cars shown above (especially the third one). He also admitted you can't identify them for definate from most of the images on this site. However the XJ12 was quite rare (1200 out of 200,000 XJ40s made) so it's very likely most of the XJ40s on this site are XJ6s.