This topic was closed for some reason, but the issue is not resolved.

There has been some talking past each other.

There are two considerations for my particular mounting problem:

1. I need to put the spacer on the non-drive side in order to get an acceptable chain line.
2. With no spacer on the drive side, on the 73mm unit the studs that the fixing bolts thread into stick out further than the face of the BB. Therefore spacers have to go between the fixing plate and the BB shell.

Louis is right that " Properly installed the fixing plate is against the BB". I hope everyone can understand why "Putting the spacer on the outside of the fixing plate IS needed on some builds to take up the 5mm excess. (Louis)" doesn't work.

I simple fix, which I have not found yet, is a 5 mm serrated spacer that would mimic the serrations of the fixing plate.