It does seem an extraordinary coincidence. But that may be due to a lack of evidence. I don't want to make TOO much of it, but the post at http://brian-mountainman.blogspot.com/2012/04/petes-puzzle.html at least raises the possibility that there might be more "bluestones" lying around Wiltshite than have been identified. Interesting.

My experience with reading the various theories over 40 years is that they all change. And they change because new evidence is brought to light: mainly through more thorough investigation.

It doesn't seem impossible to me that the Stonehenge builders --over the course of a thousand years-- gathered information on what stones were lying around, and decided to incorporate some or most of the more rare ones. So they scarfed up most of the glacially deposited "bluestones," perhaps missing an odd few of the ones that hadn't been buried in peat or outwash or whatever.

No one has surveyed every square foot of Wiltshire to a depth of twenty feet and PROVED there are NO MORE bluestones ANYWHERE --especially under the ground-- between Stonehenge and the Preseli mountains, right? Or am I, as usual, missing something?