Studland, well named!I go to Studland Beach in Dorset (UK) several times a year, its a 90 minute drive for me. Its a lovely beach, but no facilities so take your own food/drink and be prepared for a long walk.
Years ago, I'd go to a nude beach at Southsea, I'm not sure if that still exists.
I've also been to a small naturist resort in Rovinj, Croatia which was great, and other nude friendly beaches in Italy and Spain.
