Hi everyone,
Thanks for your replies. Since my original posting 2 years ago, I had
worked out that it was a Cladonia, but hadn't felt comfortable with
any species name. I know it's hard to ID some things to species from
just a photo. I'm pretty good with most natural history
subjects(especially plants and fungi), but I don't have any field
guides to lichens, so I'm fairly lost when it comes to them.
John