Fairly common in this coastal location but I don't know the ID. Looks a bit like a succulent shamrock/clover/trefoil.
No interactions present.
... but didn't realise that the leaf type can vary with location. It was the smooth, tough & fleshy leaves (and the absence of flowers / seed pods) that made me think it might be something else.
Lat/Lng: 54.252, -5.608
OS grid ref: SB650900