The eponymous summerhouse in Alan Ayckbourn’s musical retelling of the fairytale of Beauty and the Beast is in stockbroker-belt Leatherhead. But as composer John Pattison explains, the magical spot in the hills of Majorca where the pair wrote the show lends enchantment to this construct of Surrey.

Jessica Curtis’ design has the summerhouse in a leafy glade affording vistas into fairyland, and with Philip Gladwell’s lighting, sets the scene for enchanted transformations. Ayckbourn charts the gulf between the sexes and offers his characters a magical way to cross it.

Chrissie and Grayson host a garden party. They’re from Ayckbourn’s familiar dramatis personae of dotty doughty matriarchs with husbands whose basic instincts embrace booze and bosoms. Their daughters are tomboy teenager and stroppy bride; and the objects of their desire – and ire – are the first and second husbands of said bride, a womaniser and a wimp respectively

As daughter Amanda honeymoons with her new husband, her ex, bohemian artist Robert, dosses in the summerhouse, illustrating a child’s book of fairytales. Perhaps it’s the scotch that inspires him to paint a Beauty better endowed to fuel more adult fantasies, but even scotch mist cannot explain how she comes to materialise. Ayckbourn’s explanation that Robert provides a link to this virtual unreality, has acquired new computer-jargon connotations since he wrote the show in 1992.

It transpires that everyone – in Fairyland and world of Leatherhead – has a need they can only fulfil with mutual help across the magical divide. And just as Shakespeare ensures that ‘Jack shall have Jill’ after a Midsummer Night’s Dream in the woods, so Beauty shall have Beast and all find contentment.

Belle, the Beauty, can only communicate by singing, so everyone’s obliged to attempt breaking into apparently improvised song. Eventually all succeed, even Annette McLaughlin’s tonally-challenged Amanda. McLaughlin actually has a terrific voice and the mutual taming of Amanda and Stewart C Scudamore’s imposing Beast, Baldemar, provides the show’s comic climax.

In a strongly cast show, Rosalie Craig’s Belle has a voice as rounded as her fairytale figure, well matched by Michael Sheaffer’s sexy, louche Robert. Elizabeth Counsell’s Chrissie and Nick Lumley’s Grayson fine tune a comic double act. Giles Taylor as Amanda’s second, Sinclair, and Kelly Adams as the tomboy who’s clearly a beauty, elicit sympathy for dogged devotion to the unlikely objects of their affection. Watermill stalwart Paul Harvard’s musical direction gets the best from the tuneful, if unmemorable score.

Dreams from a Summer House is a show where you have to enter into the fun and fantasy. It’s in danger of floundering at the start and at three hours’ running time, perhaps takes too long to realise its transformations, but in between it is often bewitching.

- Judi Herman