Some chefs are big, oversized personalities who fill rooms and kitchens alike with the force of their charisma and chutzpah. Other, no less talented and able, figures are quieter, and prefer to let their cuisine supply the fireworks, rather than their presence. Chef Raymond Ma, who is the international head chef of the world-renowned Aqua group, is far from the shouty and dramatic character you might imagine. Instead, he's friendly, polite, refreshingly down-to-earth and keen to discuss his latest and greatest innovation for the restaurant group: crystal sushi. We meet in the Broadgate Ci...