The striking storefront of Granny Takes a Trip, on King’s Road, London, 1967; the shop was co-founded by Sheila Cohen and Nigel Waymouth, seen here (second from right) with Jess Down, Rufus Potts-Dawson, and Amanda Lear. At Granny Takes a Trip, the Chelsea clothing store whose customers included John Lennon, Mick Jagger, and Lou Reed, it was difficult to tell who was a pop star and who wasn’t By Mark Rozzo During the sun-dappled London summer of 1967, a King’s College student named Salm...