That arrangement was actually very common and would generally be worked by hand rather than shunted with an engine. A wagon dropped off could be rolled, using either a horse or a pinch bar to the far side of the point, where it could be loaded/unloaded, before being repositioned ready for collection. I suspect the wall you refer to is the loading bank, which would had merged into the surrounding land.
It is interesting to note in the earlier 1859 mapping that wagon turntables are included at the end of this siding to allow access to end loading. A similar arrangement also gave access to the rear of the goods shed. The structure in front of the goods shed had at that time its own siding, subsequently removed. Also worth noting is that the main building is marked as the school. Perhaps this previous use explains why the future station agents got such a substantial dwelling.