Don’t be thrown as I was by the funny symbol (5 dots in a pentagon) which appears just to the right of the words “Stone Circle” on the OS Explorer map. I assumed it was an obscure symbol for a stone circle but in fact the circle is somewhat further south and I haven’t got a clue what the symbol really means!
The circle can be found by walking 200m on a bearing of 230 degrees from the path junction. Don’t try looking for the reservoir for help – it has been drained and will not be refilled.