The big finish to Streets of Gold: Mumbai, an excited look at the city’s ‘wealthiest one-percenters’, was an extravagant party hosted by ‘two of India’s most coveted fashion designers’. As the programme made clear, all the guests were rich and/or famous, and all were dressed to prove it. ‘If you’re basic, you’re not invited,’ said one – which, given that the idea of the party was ‘to celebrate diversity in all its forms’ some documentaries might have considered a remark worthy of further investigation. But not Streets of Gold. As the previous hour had demonstrated, its chief characteristic – never a good one for a documentary – was a marked lack of curiosity.

Had these multi-millionaires been British, the BBC would have been much more questioning

In scene after scene, we saw or heard things that, with a spot of digging, would surely have revealed compelling and complicated truths. But instead (possibly in return for access to very rich people being very rich) this first episode of three simply pointed its cameras and marvelled at all the luxury they recorded. Meanwhile, the narrator read out a cliché-ridden, PR-style script which amounted to little more than an open-mouthed, unreflecting worship of the wealthy.

Or at least of the Indian wealthy. Had this been a BBC2 documentary about British multi-millionaires, my guess is that it would have been much more questioning and ambivalent. There was also something distinctly patronising about the ‘you’ve all done jolly well’ tone. And about the way every assertion from the assembled company was nodded through without a murmur: that poor Indians are deeply proud of having so many millionaires in their midst; that India is no longer a socially conservative country; that it only ever was because of the Brits; that the fact that ‘you suddenly have villagers watching porn’ is happy proof of sexual, even feminist enlightenment. Nor was the programme so impolite as to wonder why all the fabulous people in India are light-skinned – or to notice that one of the principals appeared to be almost constantly drunk. Granted, most of us don’t mind an occasional gawp at the super-rich. But as it turns out, it’s a lot less fun when you have a constant sense that a far more interesting story is there to be told.

Streets of Gold: Mumbai

As its name suggests, Darby and Joan – featuring retired cop Jack Darby and former nurse Joan Kirkhope – is a series aimed squarely at the more mature viewer. (After all, not only is there that pun in the title, but you also need to be quite old to realise that there is a pun in the title.) According to the publicity material, this makes the show a brave departure in the world of modern television – rather than say, yet another series aimed squarely at the more mature viewer.

Either way, the show’s set-up was carried out with impressive efficiency. In the opening scene, Joan (Greta Scacchi, no less) rang her husband Ian, thinking he was Spain, even though we could see he was in the Australian Outback. In the second, she was in Australia identifying his body. In the third, six months later and back in England, she defied her nagging, middle-aged child (a reliable motif of oldie television) and returned to Oz to drive about in a motorhome and find out why Ian had lied about his whereabouts. With still only minutes gone, she then collided/had a meet-cute with Darby (Bryan Brown, no less). As his car was conveniently undriveable, he joined her in the motorhome for what we’re told will be a weekly series of mysteries for them to solve.

The first took place at a hippy commune that Joan knew had once been close to Ian’s heart. These days, only six people were still there, one of whom was found dead the morning after Joan (but not the upstanding Darby) had joined them for some nostalgic pot-smoking. And with that, our heroes swung into action, establishing that what seemed like an accident was actually murder and going to work on the five suspects.

The whodunnit that followed was pretty perfunctory, relying on such staples as a watch that stopped at the moment of death and the killer not being left-handed. (Think Death in Paradise with none of the ingenuity.) Yet, while this doesn’t augur well for the future weekly mysteries, the overarching story is shaping up rather nicely. Ian’s fate bubbles along intriguingly in the background, and Darby seems to have secrets of his own. Best of all, Scacchi and Brown both remain winningly starry screen presences. Having apparently been friends for decades, they certainly have the chemistry required for the two main characters – but without overdoing the most annoying motif of oldie television: the would-be daring reminders that the over-sixties are still hot to trot.

Darby and Joan