Found these yesterday, growing as a widely scattered troop of about 40 individuals, on a horse dung heap at a farm.
Fruitbodies all appeared to be of the same type of fungus, with specimens ranging from just emerged to very old.
Nearest I can get to an ID appears to be
Panaeolus semiovatus - Egghead Mottlegill, but the physical size of some of these seems on the large side for that - Largest were easily 18cm tall, with caps 75-80mm across.
Any help with ID confirmation/other much appreciated.
Regards
Mike