I hesitate to criticise but I have noticed a tendency in some of drawings which include a plan (top) view and single Bofors the artists flip the mounting part drawing from starboard to port. That isn't correct; A Bofors is asymmetric and flipping it is incorrect. You would have to rotate the drawing to get the correct configuration. In this case I believe the aft port mount is incorrect. You can see Bombhead working on the problem in his beautiful HMS Triumph drawing.
You are 100% correct Wizard the 40mm single is not symetical.Thanks for pointing that out that mistake.Still it gives me a good excuse to re-post with the fix and of course Kims excellent badge.What a cracker.