LOCANDA OTTOEMEZZO, the restaurant, pays homage with logo, books and photographs to its director Federico Fellini and to actors Giulietta Masina (whom he married) and Marcello Mastroianni, star of Fellini's La Dolce Vita. That fact, plus a highly enthusiastic recommendation from a colleague, made me ready to consider the new offshoot of a Kensington delicatessen, located behind the offices of the Evening Standard, irresistible.