Weatherman Derek Brockway strips down to basics as he crosses a nudist beach in Gwynedd. Luckily, he has got a beach ball to spare his blushes! On this walk along one of Wales’s most popular coastlines from Harlech to Barmouth, Derek also rolls a cheese down the world’s steepest hill. He learns about the ‘devil in the shawl’ when he visits an old village chapel, nearly gets caught out on a tidal causeway and meets a team of women who give up their free time to keep the beaches clean and safe for wildlife