Cropmarks recorded during Royal Commission aerial reconnaissance, during the 2018 drought on 13th July 2018, revealed an oval defended enclosure on the coastal ridge to the south-east of Hean Castle. Parchmarks in grassland show the defensive circuit well, with a broad outer ditch and plough-levelled inner rampart measuring 103m x 66m, and enclosing 0.56 ha. Somewhat confusingly, the genuine prehistoric enclosure lies adjacent to two post-medieval circular tree-planting rings; it glances the larger ring to the west and underlies the smaller ring to the east.

T. Driver, RCAHMW, Oct 2019.