Ok, you've all got a pet example of "why don't they leave it in inches" but I opened the L/R manual to check the backlash on the front wheel bearing of the Disco and it wants 0.1270 to 0.1016mm instead of 4 to 5 thou. That last decimal place is 1 millionth of an inch. I'll need an interferometer to get it right.
I'm still a bit pissed off after I lined a wall with plywood, in sheets 2440 x 1220, or good old 8' x 4', and then had to cover them with plasterboard which is 2400 x 1200. The screws in the edge of the last sheet missed the studs by a mile ( 5", or 1.25 hands if you know about horses)