‘Prehistoric Axe Factory near Hyssington, in Powys: Archaeological Survey and Excavation 2007-8.’ There are also more details here.
Mmm Axe Factory.
And enthusiasts of prehistoric rock carvings may also like the photo of a stone criss-crossed with pecked lines.
Also it’s interesting to see how the freshly made axes would have been a bright blue-green, not the dull brown the picrite turns after weathering.