Ha! Quite possibly, it WAS the French.

"I'm trying to think if there's another example of people moving a whole religious structure from one place to another. I can think of bits of the original structure being incorporated in a new structure (which would make sense here) but not a whole structure being moved."

Aaah, but that involves thinking like an archaeologist, looking for precedents to back up a speculation. Quite unworthy of a TMA free thinker ;) On that basis, Stonehenge itself is of doubtful authenticity.

Much better to look at the plain evidence, and use Occam's razor. Most likely, they brought the circle with them else, as Moss has pointed out, lots of other questions arise - what's so special about bluestone, what's so special about the Preseli area etc.