I received a reply from the Museum today in answer to my query about this standing stone:
"Dear Angie, Many thanks for your email.
The stone was rescued from Tor Hill, where they also found some bones. The stone is believed to be prehistoric.
I hope that answers your question?
Kind regards,
Christine Quinn"
This threw me a bit as I was wondering if she meant Glastonbury Tor, but looking at Streetmap, there is a Tor Hill just east of the town.
(Approx ST557457).
Something is not right. This message is just to keep things from messing up down the road