the hole in the upper centre of the sidesheets is for putting a bar through to hold the bucket in the raised position for maintenance - that may not be their original purpose but it was a common use!
I recently saw a photo of one fitted with the screen on the operators' side ( to prevent the operator putting his head into the moving bucket arm ) - I've never seen one working in this state
I remember seeing one with lifting eyes welded to the upper sidesheets, although this may have been an on-site modification
''the stopes soared beyond the range of our caplamps' - David Bick...... How times change .... oh, I don't know, I've still got a lamp like that.