Aww, thanks for the lovely comments everyone
I was in Wolfscote Dale when I took the photos and have seen Kingfishers there a few times. They are often further down the river though, nearer to Mill Dale.
I've also seen them in Monsal Dale and Bradford Dale.
Another good spot for them is on the river Derwent at Cromford. I usually park in the car park at Cromford Meadows, then walk along the river bank at the edge of the field. There's a big tree growing out of the river bank and Kingfishers nest underneath it every year. Conveniently, the tree is quite close to a fisherman's seat.
I never managed to get a photo of one down there but watched them fly back and forth to the nest a few times!