I hate this ...

I too can spy the marks made by a steel bolster-type chisel down one edge of the stone - suggesting it is more recent. It hasn't been set where grazing animals can get to it and use it as a rubbing post either. That's very unusual.

There are perforated stones on Orkney. The blocker on that summer solstice sunrise row, for instance. The diameter of these holes (in M.I.) is significant - does anyone know what they are ?