The diff has now been rebuilt, twice. The first time with the correct gasket size 0.010” but this did not provide any backlash, it took a slightly thicker gasket 0.040” to give the right amount of backlash. I can only put this down to the NOS crown wheel/ pinion and bearings and maybe they were ever so slightly different.
Diff is now all installed. Dropped the brake drums and pads into the local brake shop and they will match the pads to the drums.
Assembled the trailing bogies. The nitrile bushes fit and seem to work well at keeping the grease in.
One set of springs are installed, the other boggie is installed and just the other set of springs to be painted and installed. To completely strip and rebuild the suspension has been a laborious job, but I suspect will be well worth it.
Now I can finish making the new brake rods.