Further to a thread a while back about polishing marks.
I have found the quote I was looking for.
Antiquity Vol. XXXII No. 128
p237 The Excavations of the WKLB 1955-6 Stuart Piggott.
"An incidental discovery of some interest was that on more than one of the chamber uprights, and on the southern of the
three blocking-stones, were polished areas where stone or flint axe-blades had been ground or resharpened."
PeteG