March puzzle

It’s a scheduled Bronze Age stone circle and much visited. It is where Arthur extracted Excalibur. Perhaps.

Aubrey Burl said of it: “aerial photographs have revealed mediaeval ridge-and-furrow plough-marks not only running up to the ring, but also through it as though this ‘prehistoric’ megalithic ring might postdate the Middle Ages! It does not.” However, others have suggested he may have been wrong and that it is a fake.

So where is it? The answer, and the evidence, in a week.