Well so far I have front and rear axle parts spread across most of Southern England ÂÂ

I pulled the front springs off this evening and took some measurements on one side (the side without the three bolt flange). With the wishbone jacked up so the shaft is straight out of the axle there is about 5/8" spare movement in the driveshaft (with the circlip off I pushed the shaft inwards). Haven't tested the other side but I know someone who has been running a 1" spacer on that side for several years without a problem.

Surprisingly with the driveshaft straight out the wishbone is almost against the bumpstop. Against the bumpstop there is hardly any upward angle of the  driveshaft.
I have to pick up another rear diff hopefully Wednesday so I will see what they have at the breakers. I'll take my shafts to compare.