A dunnock and a sedge warbler, maybe?

I heard a bird I thought could be a whitethroat singing from a large area of dense cover. I'm not great at birdsong, so I tried in vain to locate it to make a positive ID, but just ended up with two more questions!  The first movement I detected was this, which I'm pretty sure was not the singing bird, but what is it?  My first thought was juvenile house sparrow, but the bill seems too thin, and the head markings wrong.  Is it a young dunnock?

The second one is a bird I didn't see at all until I looked at the photos, where I noticed it in the corner of one picture.  Could it be a sedge warbler?

Sorry the pictures are so grainy.

  • Thank you.

    Sedge warbler is my second "new" species in as many days, so I'm on a roll! I'm not sure that it really counts, given I only noticed it in the photo, but I've just listened to sedge warbler song on xeno-canto and realised that's another mystery solved. I've definitely heard them, although about half a mile from this area.