SwallowHead because the shape of the river looks like a swallow. This is easily visible from ontop waden or Silbury.

Kennet=Cunnito (Roman word) Anglo-saxon = Cunt

Thanks for the kind words, Nigel. Its a bit of a big question, though! Especially considering I've only been there once! I can tell you that Julian derives the name Fyfield Down from the name Ver, the water goddess, though. And also Wansdyke from Wan (Odin) - have you heard "My Wall" on the recent Sunn O))) album? Is there a Bo Wood near Avebury (I've heard tell that there is)? If so, you can probably guess who I think it was named for! If you were to hit me with names that particularly interest you then I'd probably be able to be more helpful...

ps - I entirely agree with the interpretations of Waden Hill and the river Kennet given in this thread.