As biopics go, this has to be the least structured and most creatively ambiguous I think I’ve ever seen. It sort of follows a chronology of the life of Gustav Mahler (Robert Powell) using a train journey with his wife Alma (Georgina Hale) and a wide selection of his music as a conduit for just how we got here. It’s safe to say that the marriage isn’t exactly happy. She resents the time he spends composing and conducting and even though they have a very comfortable life with their children, she yearns for something more. He, meantime, is so subsumed in his art that he doesn’t notice, or…