Saw this on a gorse bush on a recent visit. I am fairly sure it is a corn bunting as it was a heavy. dumpy bird. Sorry about the lack of clarity but I do not possess a mega -zoom camera.
Nice photo. Not a Corn Bunting thought, it is a Dunnock.
It was too big and heavy to be a Dunnock. See plenty of them in my garden at home. Like this one.