One of the leading models from the 60s turned photographer, recalls how she became one of the defining faces of a generation — Before becoming a photographer, Jill Kennington, who just turned 74, was one of Britain’s most iconic models. She appeared on the cover of Vogue three times and was shot by the likes of David Bailey, John Cowan, Terence Donovan, Helmut Newton, and Richard Avedon. Her prolific modelling career, in particular…