TOP Gear (BBC1, Sunday) keeps on trucking, returning this week for an incredible 29th series. The motoring show is now 18 years old, several heads taller than you, eating you out of house and home, and demanding a key to the door. It has no chance of the latter.

Top Gear exists in some weird, time-travelling-in-reverse universe in which the older it gets the more juvenile its presenters behave. The rot started with Clarkson, worsened with Chris Evans and Matt LeBlanc (wheel spins at the Cenotaph, anyone?) and continues with the new trio of Paddy McGuinness, Freddie Flintoff and Chris Harris.

But that is its laddish charm, I hear you say in a bid to play devil’s advocate (have you nothing better to do on a weekend?). True, but how much laddishness is just enough?

The three made much of their move from BBC2, but if this was their chance to show the bump was merited they chose an odd way of going about it.

Their challenge was to spend 24 hours in a company car in Bolton. Talk immediately turned to the most important thing: toileting. Important, sure, but did we really need to see, or rather hear, Flintoff peeing into a container?

There were some nice moments, including McGuinness returning to his childhood home and being treated like a hero, and some garage forecourt karaoke complete with singalong crowd (filmed pre-Covid, natch). Otherwise, the hour felt stretched and the banter was thin.

Muriel Spark by Ian Rankin (free to view Sky Arts, Tuesday) was a treat. Rankin completed a PhD on the creator of Miss Jean Brodie, using the years to write his first three novels, Rebus’s debut among them. Add a lot of effort by the production team to track down informed, fresh voices, including a former pupil of the real-life template for Brodie, and you had the makings of a first-class documentary.

Rankin was a child in a sweetie shop, delighted to hold the manuscript for The Prime of Miss Jean Brodie. No white gloves, either. The freedom went to his head and he sniffed the notebook. “It just smells like literature, man.” Writers. Can’t take them anywhere.

By his own admission, Rankin succeeded only “a little bit” in uncovering Spark the person (above) rather than the writer (the latter he had down pat). It did not matter much. He added his own take, as a Scot and as a fellow writer. Spark kept everyone guessing and continues to do so today. One imagines she would be delighted by that.

Murder Case (BBC Scotland, Tuesday-Wednesday, BBC2, Wednesday-Thursday) was back on the mean streets of modern Scotland. So much of true crime coverage tries to pass as informative while being creepily exploitative. It is a difficult line to walk, and many fail. Matt Pinder’s documentaries on the work of Police Scotland’s Major Investigation Team are a masterclass in doing the right thing, for the right reasons, in the right way.

Dealing with the harrowing death of a man in Renfrew, the filmmakers were never less than respectful to the family of the victim. In the second of two films it was the chance for the detectives to have their say on why they did the job, and what it did to them. “You see the worst of humanity,” said one. “You also see the best. The bits in between you just have to deal with.” Nick Ross used to end Crimewatch with the sign-off, “Don’t have nightmares.” No chance after watching this.

Ditto new drama Adult Material (Channel 4, Monday). Set in the porn industry, it was the story of Jolene Dollar, seemingly successful actress, mother and partner. Sends the kids to private school, big house and car, etc. Sorted. But the business is becoming more rotten than it ever was in the fight for paying customers, and there will be victims (and blood).

Adult Material started on a light-ish note (Jolene in action while running though a mental to-do list), and soon plunged into something nastier and more real.

Sharp writing by Lucy Kirkwood and wonderful to see Rupert Everett as the British boss of a porn empire. A cautionary tale. We promised to rendezvous again on Life (BBC1, Tuesday) after a shaky start. Between conversations that did not happen, or happened in someone’s imagination, to the ghost wife craving toast and Marmite, I still have no idea what is going on in this drama about residents of a Manchester mansion block.

When Peter Davison’s ex-lover turned up looking the dead spit of Elaine Paige, I thought I had gone mad. Only a quick check of the Radio Times confirmed I was not hallucinating and it really was the diminutive musical star. Honestly, who suddenly springs Elaine Paige on a person without so much as a by-your-leave?

I’m beginning to suspect that Life is hoaching with dead people, like some sort of Middle England Sixth Sense.

I’ll have to come back, if only to satisfy my curiosity. Save yourselves.