See! Obviously NOT a Dipper. Can't tell what it is?...
.... Have a stunning close up then.
A Green Sandpiper.
I've seen a few of these along The Coly in the winter before but normally in the pools, backwaters and muddy margins. I've never seen one out in the fast flowing water like this. Still, you live and learn. I'd rather have seen an elusive River Coly Dipper though! :-)