Deep breath. Here goes. Winsome Pinnock’s new play about Turner opens with one of the most confusing and illogical scenes you’re ever likely to see. A teacher on a school trip is showing her pupils a Turner painting displayed in a gallery housed inside a ship donated by the producers of a film starring a famous actress, Lou, who happens to be on board wearing a sumptuous outfit for an awards ceremony, which she plans to avoid for fear that a coveted prize will be handed to a rival.