Juvenile dunnock?

This morning I could see from the bird-box camera that one of the great tit chicks was peaking out of the hole, so I grabbed a proper camera and set out to grab some photos.  However, when I got outside I found that a bird had got underneath the net that is protecting some newly seeded grass, so I grabbed a couple of shots of this bird, then undid some of the pegs holding done the net and gently coaxed it out of captivity.  By this time, it turned out, the great tit chick had fledged, judging by its absence from the box. The other three are still there, though, very sensibly in today's weather.  I snatched another shot of them this afternoon (in extras).  I'm pretty sure the little bird is a juvenile dunnock, but I'm open to correction.