I didn't see it, but heard a 'whooosh' and everything flew up into the bushes, so I presume we had a rare visit from a Sparrowhawk (one hit my window a few years ago, the only one I've seen here).
I found this little lady sitting deep into the leaves and was surprised to actually get a picture of her.
Sorry for the poor quality, found I'd got the camera on 400 ISO, not good to do that, is it.
TTTW