Re: User Error
"You don't use Metric tools on your old Ford, [...]"
In general a set of Metric spanners will fit most Imperial hex bolt heads. There are only a few Imperial sizes that are needed for some interpolations. Even then the bolt head or the spanner tolerance - or the bolt head wear - can mean the expected spanner doesn't quite fit. I have several nominal 13mm and 1/2inch spanners which are mix&match against some bolts/nuts.
Apparently LandRover put different size heads and nuts on one bolts' fitting - so you didn't need two spanners of the same Imperial size to adjust it.