Great Crested Grebes

On my walks to the Local Nature Reserve, I am always pleased to spot a Grebe fishing in the local Flash, but they are usually far away, and disappear underwater as soon as they see my camera!
Today, I spotted one on an adjoining Flash, then very quickly saw another, and was delighted that they started their elaborate mating ritual of head-waggling and feather-spreading.
I've not seen them perform this before, so I was delighted that I'd stopped to watch (and that I had my 50-140mm lens with X2 extender attached to my camera).