Mark Edmonds also did a paper on the Creag na Cailliche axe factory available on psas .
One element that is fascinating about the trade is that quality may have been important in most circumstances but there is no doubt that crap "foreign "gear is found in areas that had perfectly good stuff on the doorstep . Also depositing deliberately broken unused good stuff , sometimes in circumstances that look like surrogacy for bodies .

I'm pretty sure it's in the "Megalithic rows of Britain etc" or similar title