There is undoubtedly something exciting about the idea of bringing Trainspotting to the stage. Danny Boyle’s film and Irvine Welsh’s novel remain such defining pieces of British culture that, on paper, a theatrical adaptation feels like a natural fit. The foundations are all there. Unfortunately, while this production has moments that genuinely work, it never quite decides what it wants to be, leaving a show that feels caught between a play with music and a full-scale musical.