lobed edges, very fine thallus, white fruit bodies.
Caution: Do NOT use iSpot to identify fungi to eat!
Some fungi are very poisonous so a mistaken ID could have serious consequences.
No interactions present.
I am reasonably sure that Jenny is right that this is Ochrolechia parella. The thallus is thinner than usual but otherwise it looks correct, and I cannot suggest any other candidates.
Quite often, species of stonework can colonise wooden fencing if the fencing is impregnated with dust. I guess this is the case here.
Lat/Lng: 50.5949, -1.1987
OS grid ref: SZ568775
growing on fence by sea