When I visited, two years ago I had only the OS map and my intuition to find this one.
As baza says, it’s in a copse, which requires you to trespass. I went in winter when the undergrowth had died back and after frightening a least half a dozen pheasants as I paced up and down, I found a monumental stone, now sadly down, and pretty much ready to be reclaimed by the earth. It was undoubtedly the Hoar stone. All mossy and uneven and covered in leaf-mulch and fruits of the forest floor, it’s over 10 feet in length. This one is crying out to be re-erected before it becomes lost to us forever, as it surely will be if it is left in it’s current condition.
Goodbye Hoar stone.