Grey-brown lichen - possibly Lecanora sp?

Grey-brown lichen - possibly Lecanora sp?

Observation - Grey-brown lichen - possibly Lecanora sp? - UK and Ireland. Description: Growing on siliceous rock in the splash zone, a dark grey-brown to lighter grey-brown crustose lichen, that tests C- and K-. The thallus appears thin but cracked where visible and seems to blend into the rock at the edges; the abundant apothecia are up to

Growing on siliceous rock in the splash zone, a dark grey-brown to lighter grey-brown crustose lichen, that tests C- and K-. The thallus appears thin but cracked where visible and seems to blend into the rock at the edges; the abundant apothecia are up to 1mm in diameter and lecanorine with very dark brown to black discs.

When from a little distance I first saw this small patch of lichen I thought it was black, but on closer inspection much of it is brown, though the rims of some of the apothecia are almost a dark beige.