Julian Cope presents Head Heritage

"so extensions at both ends ?"
that's just what I'm suggesting, that's why I called them proto-henges being precursors from the central european neolithic (5000 even 6000 BC)

There's also rondels in Hungary of course, because modern borders do not make sense in prehistory,

http://korarok.baranya.hu/index.php?lng=e

And even more intriguing is current intense discussion on whether the famous calcolithic round enclosures in Portugal have anything to do with them, but I think that connection's more far-fetched and coincidental though

http://portugueseenclosures.blogspot.com.es/2012/03/0085-why-are-they-round.html

I knew there were one or two henges in Wales (hence the ??) but, again, far too few to be of much significance in a global context

Fascinating!!