http://www.themodernantiquarian.com/post/43624
"There's a couple of these perforated stones in the wall that runs down to Dakins Brook, from Thurstones"
"The hole is an irregular three Megalithic Inches by four and was originally used to fix a carved image to the stone in prehistoric times (rather than to watch the sun/moon through)."
Stoney, you're a comedic genius, you really are. I've not laughed so much, since Ricky Gervais's dance in The Office ..... many thanks