On the top of a very shaded stone wall.
Caution: Do NOT use iSpot to identify fungi to eat!
Some fungi are very poisonous so a mistaken ID could have serious consequences.
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I was looking across the web and now wonder if it is Diplotomma alboatrum? Here are two sites that kind of looked like it http://www.stridvall.se/lichens/gallery/Diplotomma/NIKA7197 and
But maybe it is Rhizocarpon lavatum!! I will try and collect a piece.
D. alboatrum is variable and I cannot entirely rule it out. However, it generally has a very chalky white thallus and raised, round, neat apothecia that initially are strongly pruinose. The Stridvall photograph you cite shows it very well.
Lat/Lng: 52.4, -4.0
OS grid ref: SN6689