But a new restaurant just north of Oxford Street intends to change all that. Six-13 - named because of the 613 mitzvahs, or Jewish rules for living - offers the intriguing possibility of modern Jewish fusion food. (Now I really have heard it all.) Its kitchen, despite being run by gentile Steve Collins, formerly of Quaglino's and Circus, adheres to stringent rules. However, he doesn't have separate meat and milk kitchens for the simple reason that there are no dairy products used in the cooking. As someone whose arteries are furred from daily doses of butter, cream and stinky cheeses, I find this inconceivable.