A most interesting thread - thanks all!
I still remain uncovinced about the murder having occurred on the gallery, as opposed to the staircase landing.
The description in Lloyd's news is rather clear, as it mentions the dark staircase.
Besides, having a single flight stairs would seem to be an odd departure from fairly standard structures..
To my mind, the staircase didn't go all through the building but was as crammed as the one in St George's buildings. Therefore the protruding part at the front was probably a part of an apartment. (The Wm. Stewart photo of the G.Yd front even shows flowerpots on the widowsill.)
Interestingly enough, two separate issues of IPN show the body laying at a spot that is very reminiscent - or a mirror image of - the upper Winston Ramsay pic - right down to the privy doors. (The lad would be standing at point "X" on the plan)
I know IPN is often less than accurate, but I reckon this time they did a little bit better.
/jake