This area later became the parade ground, in those days it was known as the cricket and football field some buildings on that area were constructed before the boys came ashore. Difficult to find exactly when as no records exist – although some were erected around 1903 such as a disinfector house, temporary sick quarters and recreation block where 37 – 40 messes were later to stand.
The stays etc; for the mast can be seen on the left so the photo must have been taken in or after 1907

Much info of that time comes from written comments left by boys who were there at the time – the buildings shown behind the footballers did stand where Nelson Hall was later constructed – the buildings in the background were in those days, the canteen and changing rooms etc:
Take a look at the photo of Sunday Divs 1920 https://pbase.com/hms_ganges_museum/image/169354595
and Sunset 1920s https://pbase.com/hms_ganges_museum/image/169354596 and there they are to be seen in the background!