6 km from Priddy circles is Gorsey Bigbury, http://www.themodernantiquarian.com/site/3842 described as a henge but presumably later... Think it was Skinner who described it looking like a "bull pit" with high banks; its banks are much lower now due to farming practice.
Sometimes we all get stuck with the same old words to describe the prehistoric circular patterns we see.. truth is we JUST don't know how they were used ;)