Amongst the charivari of billionaire yachts in the impossibly scenic vieux port of Nice, three tall masts reigned supreme. These belonged to the ultra-sleek motor-yacht Le Ponant. And, whilst I was not a guest of an oligarch aboard the ostentatious, bling-brimming gin palaces, I climbed aboard this incredibly stylish yacht of Compagnie du Ponant with more than a soup