Jimit mate that's the wrong stone! what you've got there is fossil imprints.
The pollishing stone is in the main corridor after the first chamber on the left.
It is a very smooth long area which was probably just used for pollishing not sharpeneing,

I cannot find a photo on here or megalithis.
It looks like this
http://peteglastonbury.ic24.net/WKPollishing.jpg
PeteG