There I go again wishing to see rather than observing. Dusted off bins advises me that the Arctic Tern posted previously is actually a Common Tern. I was relying on the lack of black tip to the bill but he points out not all Common Terns have this and in addition its too orange, the bill and legs are too long and the black primary plumage too diffuse. Thanks Alan. I'll stick to getting unusual angles rather than unusual birds.
Illustrated ..............Common Terns at Whittle Dene early August.