"One thing's for sure, the local Wiltshire dialect would have rendered the 'a' in Waden as an open vowel - ie Waaden, not the closed vowel suggested by Weedon."

I suppose pronunciation before tape recorders is always speculative but I was interested that Samuel Pepys wrote about his visit to Avebury where he saw "Selbury" Hill in which was buried "King Seall". Bearing in mind his guide was a local "countryman" I reckon it's highly likely those spellings (that appear nowhere else) are pretty reliable evidence of the laid back Wiltshire drawl in use at that time. Whether Waaden or Weedon would be consistent with those two examples I'm not sure.

He also refers to "Abebury" (again, uniquely) whereas Stukeley and John Aubrey have it as Abury and the historian Dean says it should have been Abiri. But I wonder if Pepys is the one that is right in terms of an exact rendition of the sound he heard, if not the name itself, and that the locals spoke in an extremely laid back slow fashion which appeared to add an element to the name even though they didn't mean to - thus, King Seeeey-allll and Abe...bury. A bottle of Saki will help convince you.

One more complication is that I read John Aubrey is on record as specifically saying the correct pronunciation was the same as his name, Aubrey.