I have finally managed to see one - I was on holiday in the Norfolk Broads and talkign to the person on the boat next to mine while moored up and he happended to be a bird watcher and I said "I hear there's loads of Kingfishers around but can;t seem to spot any"
he replied " They are very difficult to spot but there's one over there in sitting on a branch"
From there he guided my eye to the spot and I still couldn't find it until I got eh 100-400 out and eventually spied him sitting proud as anything in the shade.
Here is what I got from the 5D at 400mm ISO 3200 @1/100 F16 Handheld standing on a boat in calm water.
I am so pleased that I even got a recognisable pic.
Full Frame
Heavy crop
Roger