Ross Sands in Northumberland is 1.5hrs from Edinburgh but well worth it, gorgeous deserted beach 4 miles long and predominantly nudist, though maybe 20 people at most.

A1 south, after turn-off to Holy Island (8 miles over the border approx) continue to 4th turn-off (2 miles further on) to left marked Elwick, cross main railway line, continue through Elwick and at bend in road with a phone box is tee junction to Ross on left, it's a dead end. You have to park on kerb outside village and walk through farm to beach, about half an hours walk. Once in dunes head left to North, nudist areas usually start after 10mins further. There are miles and miles of dunes here and if you continue to the spit of land called Guile Point you won't see another soul all day. It's fab.

Thanks to BigJock