I've got another one now. I saw this on the Llandudno west shore beach but wasn't sure if it was an intentional plantation or a native. The whole stretch between Llandudno and Conway was a curious mix of sea buckthorn, hebe's and mostly goji berries (literally hundreds of yards of them, dozens or yards deep) plus these which I guessed were phlox?
I didn't think much about it until today when a friends labradorite came out of the bushes with some attached to its harness. A quick inspection discovered a decent sized clump of them. It obviously runs at the root and is just as happy in a semi woody area as it is on the beach. The flowers are more pink than they look and seem to fade to a whitish