Drive through the sleepy village of Lessac on your way to Confolens and you may think you are one of only a handful of visitors each year to this pretty Charente village set back off the main roads. But follow the small blue signs to the Domaine de Boisbuchet and within minutes you enter one of the region’s best kept secrets, a world of cutting-edge design accompanied by the persistent murmur of teams of international students creating, building, designing and experimenting…