Sister Act is being turned into a musical that is about to open in Atlanta on January 17 en route to Broadway. But if The Sound of Music hasn’t already given you your fill of singing nuns in London, the London fringe is fighting back with a spirited (in every sense) musical biography of Sister Wendy Beckett, the contemplative nun who in the eighties did for the appreciation of art on TV what Delia did for cooking, making it both accessible and popular.

She now lives in the east of England, according to a programme note, devoting her life solely to monastic solitude and prayer, so at least she’ll be spared seeing the show that Marcus Reeves and Beccy Smith have awkwardly devised to throw her back into the media spotlight.

Postcards from God needs to be returned to its sender for now, though. While Omar F Okai’s production, on a bright pop cartoon of a set with its nod to Lichtenstein, has a relentlessly¬†chirpy energy and sincerity (like the character it celebrates), the tone of Marcus Reeves and Beccy Smith’s book veers from over-reverential, earnest affection to making nuns seem an object of fun, and Reeves’ eclectic score doesn’t reconcile those difficulties. Myra Sands is a delight, though, as Sister Wendy.