As far as 'The Circle' is concened, Q said earlier to follow the wives. This being so, I theorise that the Circle is a coven, presumably of 13…
MOD Main Building, which is where the UK Ministry of Defence is based is almost smark-bang in the middle of the ariel photo. It's the 4 x green rectangles joined by 3 x grey rectangles.
I've had a quick dig on Le Cercle and it's an extension of Penis Club. If we're after the wives then this isn't the circle Q alluded to.