>Tombo did the etymology of Sul and Sil as a sun word (can never get back to his essays or I would give the link)...<
Yes, thanks moss, I have read Tombo's stuff and can give you the link if you need it (on my way out so it'll have to be tomorrow).
Seem to remember there was a thread here sometime back that discussed the importance of water in the Avebury area but can't remember where that was - fascinating stuff though.