There was a DME circular which mentions the BSA front saddle mount, its in the highest priority list "Immediate action".

B.158 6/7/41 1. Saddle front mounting 2. Battery fixing bolt B.S.A. M/C's

Unfortunately we don't have the circular to check, but it could be that its to do with retro fitting a grease nipple to early machines which didn't have them? This may be evidence that these circulars didn't reach every machine?

Rob

email (option): robmiller11(a)yahoo.co.uk