It was the long hot summer of 2013. The world's media had been on Royal baby watch for weeks in the scorching heat outside the Lindo Wing of St Mary's Hospital in London for the birthday of Prince George, William and Kate's first child. I had the idea to give the reporters a cool break from the heat, so we flash mobbed them on behalf of Kit Kat - taking everyone an ice cream cone and stuck a '99' Kit Kat finger in each scoop.