Been listening to BBC Radio 5 ever since this happened... rated A1 in level headedness!
Just reporting the facts as they seem to be, and then the eyewitness I've reported who seems to be a very sensible young man, trying to say clearly what he saw...
he even said to start with it hadn't occurred to him that the engines were quiet, because of all the other aircraft in the vicinity and he took it for granted it was making the normal noise... It struck him a short while later the one nearest that he watched (apparently) rear up and then drop wasn't itself making (much) noise.
He was a cyclist on his way to work, alomg that A9 I believe, so he'd be used to watching them...