Cant be sure but I think Cow Castle is on Exmoor to the North .
Also rather unhelpfully a cool collection of barrows near the nine stones could be the Poor lot barrows

In case there's the vaguest interest in this:
http://www.pd49.dial.pipex.com/places/wells/wite.html

A little junction off the A35, opposite the turning to Morecombelake/Whitchurch Canonicorum (approx SY400941) leads you to the footpath which takes you to the well. The well, as shown on the website quoted above, is signposted, and obvious once you get there due to the unobtrusive wooden fence (to keep the cattle out, I presume!)

The path then continues toward St Gabriel's Chapel and on to Golden Cap...

G x