Looks like some sort of fungus, nothing I,ve seen before

Looks like you've got a bark mulch of some description - this saprophytic fungus is associated with that, I'd imagine, unless you've dead stumps in the ground, and its spread its spores over the nearby concrete. Remove the woody mulch and you'll remove the cause, but its most likely harmless anyway. You should, though, check the woody plants in the vicinity to ensure there's no sign of disease or rot on any of them, particularly at the base.