Don't think I can answer that question on new research....
Jodie Lewis is the expert on the Mendip's prehistory...think her latest book is 2008..
http://capra.group.shef.ac.uk/2/upwards.html
It seems that the henges/circles might have been a prototype between causewayed enclosures and henges and the Priddy lot do not fall into a 'proper' henge category having an internal bank and outer ditch, plus of course a timbered rampart which would have made viewing impossible. Interesting about the swallets being enclosed, and Larry Bull says something about the 'entrances' facing towards Wales, Somerset and Gloucester..
And of course, though the Priddy circles bear some resemblance to the Thornborough ones, down in the west 3 grouped stone circles together can be found at Stanton Drew and Avebury....