There are very similar terraces on the hill next to Stantonbury (its name escapes me). In fact in the surrounding 20-30 miles in all directions (and further) there are many other hills with the same style earthworks which are all as far as I know medieval terracing.

When one looks into the history of draining the levels, starting with the Romans and moving onwards to recent times, its apparent that extra land has always been at a premium in these parts. I believe the monks in the middle ages were the main culprits...