Robert Louis Stevenson died in Samoa in 1894, Paul Gauguin in Tahiti in 1903, both after struggles with sickness and — especially in the French painter’s case — lack of money. Is that coincidence sufficient to justify the double bill that Nigel Planer — he who starred in The Young Ones and wrote the spoof theatrical bio, I, An Actor — has created for the little Finborough Theatre? Watching the excellent Sean Murray as a chirpy, death-defying Stevenson in the first half and a bitter, suicidal Gauguin in the second, I thought so. At other times I wasn’t so sure.

As Planer’s title makes clear, Polynesia is in transition, thanks to the colonial powers and their missionaries. Indeed, an islander gabbles nervously about his love for Jesus, denying that he’s eaten “long pig”, then drunkenly admits that as a boy he ingested a white trader and still thinks it “taste good, make me strong”. The old deities, the ancestral ghosts and those secretly nostalgic for cannibalism haven’t quite surrendered to a Christianity that Gauguin, in particular, finds repellent. “To blasphemy” is his boozy, bleary toast as he awaits arrest for, among other things, sculpting an obscene image of the local bishop.

He would, he says, rather be eaten by islanders than buried in sacred ground. Gauguin’s fierce anti-clericalism, something he surely shares with his author, means that his play is the stronger and more purposeful.

The garrulous, too garrulous, sometimes tiresomely garrulous Stevenson has no such clear agenda, though he doesn’t much like “the grey dampness of our shabby civilisation”, presumably meaning low-church Edinburgh. What both men share is a love of Polynesia, though in Gauguin’s case this goes unreturned. His current mistress is Nicole Dayes’s Teha’amana, an exotic beauty who looks as if she’s just sauntered out of one of his paintings, and she rages at him for failing to buy her new clothes, make-up and fashionable Parisian bric-a-brac.

The feeling grows that Polynesia hasn’t been — and probably can’t be — fully Europeanised and that neither of these great Europeans is or can be as Polynesian as he’d like. The result could, I suppose, be categorised as a meditation on cultural identity and — with Amanda Boxer playing both Stevenson’s pushy, put-upon American wife and a blind island witch who senses the bourgeois ambition in Gauguin — quite a complex one. Myself, I left the theatre impressed by Planer’s curiosity and intelligence, but thinking he could be sharper, crisper, and, when Stevenson is in full florid flow, less wordy.

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