Sorry chaps. Hadn't realised they would come out so small. Busy day on but I'll see what I can do later.
The Royal Armouries have two Long Lees that have bases on them for the Jeffery scope, & long rifles were also fitted with various target sights in the marksman's role, particularly early on in the war. I also have a Watts scope in Alex Martin side mounts that was removed from a LLE & was the personal property of a Colonel (who wrote his name on the scope case). However, I suspect that this may have been a one off, as were so many. This heterogeneity of designs makes the study so rewarding & frustrating both at the same time!
Rob, are the HBSA articles available generally on line? I only have two hard copies, one of which is promised to a good friend.
Ian, I haven't looked at the Spielauer book recently & was speaking from memory, but I'll double check what is shown in case I got it wrong. The Evans rifle at the IWM is indeed the large cast aluminium mount that locates to the trigger guard of the SMLE.
Being a techno-dummy I'll see if I can figure out how to resize some photo files later so they are uploadable, but so that they don't come out too small, as clearly happened above. Bear with me!