Canmore says that this stone is well known in the area. So when I asked some people about it I was surprised to learn that nobody had heard of it. To be fair I was given directions to The Cloch (RSC) and to a cairn at Shiels (I'd been there earlier). Probably the fact that this stone is within the grounds of Lathallan School and behind a wall probably explains it loneliness.
Eventually I asked at the lodge to the school and was given directions. Enter Johnshaven from the A92 and stop at the first crossroads. To the north is the entrance to Lathallan School. Thru the gates and head south on the edge of the playing field to the bottom south west corner. In amongst the nettles is the well shaped but pebble dashed stone standing at an angle. It would have stood at 1.2 meters at it's full height.
After taking a few pics I left the stone alone. I wonder how long it will be till it's next visitor. It might be a long time.