DUBAI: “Blitz” is a throwback in more ways than one. Acclaimed British director Steve McQueen’s latest movie, now streaming on Apple TV+ after a short cinema run, is a period piece anyway, set in London in World War II during the titular German saturation-bombing campaign, but the film itself — the narrative and pacing particularly — also seem to be from the past; a straightforward rip-roaring Boys’ Own adventure anchored by two excellent performances from newcomer Elliott Heffernan as nine-year-old mixed-race George and Saoirse Ronan as his single mother, Rita.