TRAVEL for the Arts (071-483 4466) is offering packages to the New York Metropolitan Opera to see Placido Domingo in a new production of Verdi's Stiffelio and Kent Nagano making his conducting debut in Dialogue of the Carmelites. The trip, from 1 to 7 March, costs pounds 767 and includes return flights with British Airways, accommodation at the Salisbury Hotel, a backstage tour of the Met and tickets for the two performances.