Pink or white Silene
Campions are a big group and like a variety of habitats, and grow to a variety of heights to 90cm. They are generally in shades of pink or white depending on species, and you can see that all the white ones I spotted have a pink tinge on the calyx.
Campions on the coast
Two campions I have spotted within metres of the beach are Sea campion – Silene uniflora / maritima at West Beach Whitstable Kent and Bladder campion – Silene vulgaris on Seaford Head Sussex.
Red campion inland
I did spot red campion – Silene dioica recently, on the edge of woods. The second picture possibly shows better the hairy nature of the stems and red calyx, and the white eye.
Blog posts mentioning Campion – Silene are tagged Campion