There is a good place to do this at Stone Point, but I have to say I've never seen people stay remotely as clean as in the linked video. A transom fitted shower is essential.
Much less fun when you do it by accident........having fallen in off the dinghy in the Roach trying to get a rope off the prop I couldn't get back on board. I had to swim ashore, climb up the mud and walk all the way to a phone box on Foulness. The mud gradually hardens as you squelch along and the man in the Land Rover with the flashing blue light had real doubts about where i had come from.