I've enjoyed following the Avebury digs at
http://www.users.myisp.co.uk/~gtour/frameset.htm thanks Pete!
Looks like we are going to find out just how long the Beckhampton Avenue could have been. If it did indeed go all the way to Fox Covert, then that means (by my crude calculations) that if you wanted to walk the avenue, from the Sanctuary to the circle, then to Fox Covert, it would be a three and a half mile journey?
Wow, they weren't kidding when they built Avebury, were they?