Just to add (a little late) the goods shed was definitely used for school lessons. I attending Somervale School from 1975 until 1982 and we had "plastic craft" (yes it was a subject!) sessions in the old goods shed in the 1975/76 timeframe. This generally involved setting fire to bits of plastic and filling the room with smoke. I do remember it being very cold in there during the winter and getting soaked getting there when it was raining as its quite a way from the actual school.
Dave