Sorry to join this thread so late... like ten years too late... but I actually know where that photograph was taken and by whom!
It is at 2nd Western General Hospital, Stockport St George. It was taken by Harry Clarke in approx December 1917. I know this information because I have the original magic lantern slide.
In addition I'm currently researching the history of the Military Hospital based at St George's School.
I can now even name the nurses - the Sister in Charge is Sister Annie Mary Flynn from the TFNS.
