The Pure Nacional tree once at the heart of South America’s chocolate industry was believed to have been lost forever – until it was recently rediscovered by accident in Peru. Travelling to the Marañón Canyon in northern Peru is like stepping back in time. Mud-brick houses dot the hilly landscape. Electricity, which arrived in this area just three years ago, is only available in a few homes, and supply can be inconsistent. It only works about five days a week and you never know which five days these will…