These images are of the Dipper suspected to be of the Black-bellied race C.c.cinclus.
The bottom image shows pale tips and fringes on the wing coverts and tertials aging this bird as a first winter. All three images show a brown band below the white chest, though not chestnut, the presence of this band would probably prevent the bird being accepted by a rarities committee. Having viewed several images on the internet of Black-bellied Dippers they show the black belly meeting the white chest. Looking at literature the underparts of a Black-bellied Dipper are uniform dark which the above Dipper clearly doesn't show. Also both British races and the central european race can have a dark brown band below the white chest making the above bird difficult to racially identify.
Thanks to Stephen Lilley for the images.