Like at Poulyot we saw the sign but couldn't immediately see it. Moth noticed something lurking 50ms away from the laneside to the right at the edge of a field of tall maize (I thought it was old farm equipment) but he got out to have a closer look. And there it was.
A tight group of uprights leaning inwards like the swords of the three musketeers support a really square and flat capstone, just like a rustic table. It was richly veined with quartzy stripes, which is surely the reason why this stone was selected for this purpose.