It's not obvious, but it is visible from the road. There's also a very small plaque marking it on the right hand side as you approach Glastonbury. As you pass through West Pennard, you hit a straight section of road. You'll see a left hand turn towards Baltonsborough just before the road bends. A short distance further on, there's a cluster of houses. This is where the road passes through Ponter's Ball. I've got some photos at home which I'll posy up when I get a chance and then I'll chuck a link into this thread.

You might like to try this site http://webapp1.somerset.gov.uk/her/map.asp?flash=true the Historical Environment Record which is a fantastic resource. Just click on the site info and Bob's your Auntie!