SY9486 : Slepe Heath Any ideas what the concrete object might be? There's at least one more in nearby Wareham Forest but they seem unconnected with any marked boundary.
The only explanation I can think of is that they are relics of WWll army training areas which covered much of the area. Even so the shape is intriguing as it seems unnecessarily complicated for casting out of concrete. On the other hand, a well greased milk churn with its bottom cut out would do very well. Dig a hole, place the churn in position, fill with concrete and next morning lift the mould clear with handy handles - maybe.
Brian