This is the fourth time I tried looking for this panel. Somehow I always ended up arriving late in the day and with fading light levels and plenty of discouragement from the people in the house next door, I never managed to locate it.
This time I beat my way into the wildly overgrown disused graveyard with my tripod and began inspecting the fallen gravestone, mostly barely squared off rocks. After half an hour searching the small clearing I was just about to give up. Wading through the waist-high thorn bushes, my feet kept hitting larger and larger stones, one stone in particular had a large flat triangular face and more hacking revealed a faint arc formed by dirt resting in a groove.
Five minutes of jungle clearing later, the full face and some nice deep cup marks could be seen. With a little side flash, a rather wonderful panel appeared on the camera screen.