The reason for that, I believe, is they are just as accurate as land rover were on the production line. These were hand built vehicles and lots of shims etc were used to get things to vaguely line up. if you measure two theoretically identical vehicles you will find differences in dimensions.It's really odd. You'd think that the likes of SP and Richards would be red hot on dimensions, but in both cases I've found inaccuracies and not heard a peep when I'v emailed and told them.