The English name is Cornish Heath because its main area of occurrence in the British Isles is the Lizard Peninsula in Cornwall. It does occur in Ireland at two sites - one on the dunes at Murlough in County Down, where it is certainly a garden escape (it is a popular garden plant), and one in County Fermanagh not far from Belcoo, where it may be native. It grows with other heathers, and flowers about July ~ August. Outside the British Isles it is restricted to Spain and France.
All names: Erica vagans L.
NBN Atlas mapping: Species account : NBN Atlas UK Species Observations database
iNaturalist: Species account : iNaturalist World Species Observations database