I too cherish the 'purity' of TMA, but it's not as pure as we all think. We have Cornish crosses, ogham stones, Sutton Hoo!, Iron Age stone forts, brochs, souterrains, tree chimneys (they have to go surely?) ... there's quite a list of stuff that breaks the guidelines, but most of the breaks are fuzzy.
I remember a comment by McG a while back about some of them (was it brochs or souterrains?) where Julian was asked what he wanted to do. They stayed - the new book does stretch the time-frame of TMA quite a bit, but it does remain pagan. This, rather than 'pre-historic' is the key to TMA I think (just my thoughts - not set in stone and enforced by a collie :-).
The question with wells is - why were they Christianised? They're hardly churches are they? It doesn't fit that the early Christian missionaries should come into the west and suddenly make wells holy or sacred - unless they were simply handy as baptismal fonts. It seems more likely (or at least equally likely) that the worship of water at springs and wells was so entrenched at the time of their arrival that they had to absorb them into the new religion.
