For Justin Sullivan, singer and guitarist with long-standing rock collective New Model Army, fame and fortune were never the primary goal. “We didn’t want to do what you have to do to be a big band,” he says. Formed in Bradford in 1980 and still going strong, New Model Army – led from the front, as ever, by founding member Justin – put out their 16th studio album, Unbroken, in January. Expect to hear a number of songs from it when the rock quartet’s tour rolls into Cambridge next week. “Lots of new songs to play, which is always nice,” says Justin, speaking to the Cambridge Independent while d…