Just flew in a S.W. direction over London. Looked like the type you would see in the old troop carriers from the Vietnam days. I think they were referred to as Hueys? Looks like they maybe heading towards Windsor.
See Here ,...http://forums.radioreference.com/on...r-urban-night-training-12-14-july-2011-a.html This training seems to go on yearly at different times ,...If what you saw are the same spec ops types ,..then you wont hear anything on milair ,..we were able to capture the frequency they were using however it was encrypted ,...you may here them calling tower or on-route frequencies , if you see them at your local airport , you may also notice some suv's that have portable antenna setup during the runs ,..