Confidence: I'm as sure as I can be.
Notes: Again I am putting in a vague, provisional name to counteract a certain misidentification. I am afraid this is not a Caloplaca of any sort, let alone a tiny, granular species that is restricted to coastal rocks. [Inland records of C. britannica are now referred to C. arcis, or were misidentifications of various elements of the C. "citrina" complex.] The orange colour is not a pigment produced by the lichen; it is excess iron oxide that the lichen has taken in from the stone and exuded from its surface. Quite a few crustose lichens do this. In this case, the definition is not clear and it most probably is one that needs microscope work, so I am not going to suggest an identification.