On visiting the new visitor centre at Lijssenthoek on 28th July 2014 I found that one of my photos of Arthur has been included in the exhibition (It is the one of Arthur outside his hut going off to play hockey and is there as an example of what the staff did in their free time, as and when there was any!).
I was also able to look at some digital versions of the entries in the War Diary and there was an entry for 29th April 1920 that says:
"Capt. A.H. MORRIS R.A.M.C. proceeded to England on Demobilisation"