Still on my thing about lichen, here are some more pictures. I did a tentative Google to see if there was a quick and easy guide to lichen identification. Once the guides mentioned the fact that the colour can change according to whether the lichen's growing in sun or shade, and that a bottle of bleach is a handy thing to have about you to fine-tune your identification, I'm afraid I gave up. Oh, and there's also around 15,000 of them.
So, for the moment, I am content to admire and remain ignorant, but what an amazing thing lichen is.