On 1 July 1961, a beautiful 17-year-old girl appeared on the cover of Paris Match, then in its heyday: ‘C’est une deb,’  announced the cover, the once upon a time annual British ritual having crossed the Channel to the land of cheese. Her name was Cristina de Caraman, daughter of the Duke de Caraman, and she was so pretty and angelic-looking that even my mother, who was always after me to marry a Greek, told me she was the kind of girl I should get hold of rather permanently.