Peter Shaffer's 1987 play is a love letter, not quite to the theatre, but to the power of make-believe, the joy of a good story well told. I'm not sure this odd play is that good a story, but starring Felicity Kendal and Maureen Lipman, it's well told at least.

Kendal plays Lettice Douffet, a tour guide at the most boring stately home in Britain, who feels compelled to embellish her script. She's caught out by Lipman's straight-laced, schoolmarmish Lotte Schoen of the Preservation Trust, yet the encounter sparks an unlikely friendship.

It takes a while getting there in Trevor Nunn's enjoyable but utterly unchallenging production. Being ticked off for telling porkies in a posh house is hardly high drama. It's when Lotte makes a visit to Lettice's basement flat that the play crackles, as the pair find a common ground in a love for the past: Lotte loathes modern architecture while Lettice has a passion for deaths of noble historical figures. Stir in a little of her homemade Tudor hooch, and the scene is set for women behaving badly go LARPing.

Still, from the start both these actresses are glorious, individually but also in their tender interactions. With her eccentric clothes and grandiose gestures, her fondness for theatrics (her mother ran an all-female French Shakespeare troupe; how en vogue!) and a disdain for the "mere", Lettice is a batty creature but an utterly loveable one. Kendal's big ol' flashing eyes, and her seductive gravelly voice, sweep the audience into her world just as she does the prim and proper Lotte.

As the straight foil for all this effusiveness, Lipman couldn't have been better cast: it may be a comparatively reserved performance, but her eye widenings, haughty sniffs and the arpeggios of anxiety she plays with her fingers speak volumes. She's funny, but suggests a depth of emotional investment too. Whether or not the relationship might be a romantic one isn't made clear; Lotte's pronouncement that "my life began again when I walked down this staircase" seems more than mere chumminess, but it's left open.

It's a bit of a daft play, only worth putting on with two good actresses at your disposal. But it's also quite long, and some of its incipient oddness isn't allowed to breathe in this bubbly, bright production: the compulsive desire to re-enact historical deaths isn't as charged as it could be, while Lotte's urge to take direct action against ugly buildings feels adrift in Shaffer's play, more a conservative bugbear writ large than a storyline that lands a punch.

Robert Jones' design dominates the first two scenes: a vast, stage-size painting in a heavy gilt frame shows the stately home and then London streets. It's an intrusive bit of scene setting, and if meant as a reminder of how lovely fancy old houses are compared with nasty new modern buildings… well, it doesn't work. Lettice's artsy flat is, however, recreated in lovingly chaotic detail, all William Morris wallpaper and threadbare chaise lounges. The whole thing is a jolly romp, which despite some ‘debates' about the value of architecture vs people, truth vs lies, nonetheless feels about as vital as deciding whether to put jam or cream on your scone first. But Kendal and Lipman serve it up with panache.

Lettice and Lovage runs at the Menier Chocolate Factory until 8 July.