Sorry to put up this rather sad post but the youngster in the photos was found, sadly demised, on my patio next to the bird feeder.

The question is, what is it?

First thoughts might be a young robin or dunnock as there are youngsters of both species in the garden. None, however, with the reddy-brown rump and tail feathers.

Black legs and bill match young redstart but not in a north Cardiff garden surely?

All suggestions gratefully received.