I've only seen pied wagtails; I didn't know we got other varieties here! Just looked up some grey wagtail pictures, and it's very cute. I'm glad you got to see one!

I love watching them in the bird bath - they look like they're really enjoying it.

I was at Chiswick Gardens with my mum a couple of years ago. A little artificial waterfall feeding into the lake was switched on while we were sitting nearby, and all the seagulls immediately took to the air and started cawing and flapping around it. I thought at first they might just be trying to wash, but my mum pointed out that they were having fun, and it completely transformed the scene for me. As soon as she mentioned it, it became clear that they were making a racket because they were excited. It was endearing!