Clapham, Tutin and Warburg describe its habitat as such - Crevices of mountain rocks, ascending to 3850 feet and on sea cliffs in W.Scotland and Ireland.
The Atlas says much the same - perennial herb which grows on seacliffs and in mountains in rock crevices and on moist ledges. Although descending to sea level in N.W. Britain and Ireland, it is usually found above 300m (my italics). This plant is just a few metres above sea level.