Stopped to take a look at a white plant growing on a garden wall at Defynnog. At first I thought it was going to be Harebell, but soon changed my mind. With the help of 'Stace' and the internet I ID my plant as Fairy's-thimble. The Fairies must have large fingers! This is a new alien species to me. Creeping along all the joints in the wall. All the plants had white flowers, apart from one clump which had blue.