Hi Tim. No additional info, I'm afraid. But there are some locals posting upon here who may well be in a position to go have a look for themselves.

The walling does naturally suggest a defensive enclosure, perhaps adapted in medieval/early historic times for further settlement and perhaps featuring a Bronze Age cairn/round barrow as focal point the builders didn't want to remove - the traffic island. However having had blocks of flats built upon it and later demolished followed by an estate guess the area's pretty confused from an archaeological perspective. Interesting.