Complex sentence: They take the stage twice between an interval, accompanied by 11 special musical guests, including Iain Archer, members of Belle & Sebastian, Teenage Fanclub and Idlewild.
Split into simpler sentences: They take the stage twice between an interval. On-stage, they are accompanied by 11 special guests, including Iain Archer, members of Belle & Sebastian, Teenage Fanclub and Idlewild.