You enter a tent containing 10 hospital beds and lie down on one of them. The lights dim and you’re transported back 100 years. Your name is Harry. You’re a young soldier, wounded in the trenches, watching a Charlie Chaplin film projected onto the canvas over your head. The delicate slapstick, as the little tramp gets into a balletic fight with a stranger on a windswept beach, regresses you to memories of seaside holidays. Then a mortar detonates, shockingly close. And so it goes on. The genius of this time machine of a creation by the immersive specialists Sound & Fury is that it focuses not on the Great War itself, but on the ways in which soldiers tried to distance themselves from it. The show is too short, lasting no more than 15 minutes. And some of the madeleine effects are pat: an explosion reminds you of a fireworks display, and so on. But it gets you there.