Adapted by Tony Grisoni from a novel by Brian Aldiss, this arty UK mockumentary charts the musical career of incestuous twins (played by Harry and Luke Treadaway) born conjoined at the chest in a remote corner of England and recruited by a promoter in 1974 as lead singer and lead guitarist for a band called the Bang Bang. Directors Keith Fulton and Louis Pepe (Lost in La Mancha) are too preoccupied with hip cleverness to have much else on their minds, and the music is so-so. Among the phony talking heads are Aldiss and director Ken Russell. R, 93 min. (JR)