Have a look and if it is simply an un-named well I guess I'll have to remove it.
Present aperture 0.7m square , water at 1m down , present bottom 1.4m below aperture. Straight roof projecting over lower wall 0.6m and depth 0.3m , corbelled roof projecting over upper wall probably not so much and 0.4m deep. Only the lower wall is drystone to the bottom. Not clearly evident in the photos (http://www.themodernantiquarian.com/post/28875) is that the base of the upper wall is either a large stone with an angle or two big stones 0.8m and 0.5m close-fitting , giving the bottom of the well a 5-sided appearance . The stone over the upper right of the aperture is 0.7m x 0.6m , the larger portion of the capping has fallen into the well with the soil.