Last night's viewing: Who Do You Think You Are?, BBC1 Big Bad World, Comedy Central

Gary Lineker's family is fascinating. But not necessarily the ancestors he found with the help of the crack squad of genealogists in the Who Do You Think You Are? team. More interesting is the world of his brother, Wayne. Wayne – the black sheep Lineker – was once sentenced to two and a half years of bird for tax fraud. He also turned up on ITV's The Only Way Is Essex and runs a raft of Lineker's Bars in parts of the Med usually seen in the backdrop of Sky1's Ibiza Uncovered. The guy's a card.

Likewise George, Gary's son, whose demi-playboy lifestyle is chronicled gloriously through the Daily Mail's "sidebar of shame" and the famously Kierkegaardian utterances of his Twitter feed (for instance, Monday's: "Ever seen a bird look better after they had their lips done than they did before? Looks like a wasp's stung them.") George and his uncle Wayne in a bar, that's a documentary I'd watch.

Instead, we got good old, clean-cut Gary. He was, at least, aware of this subtext. When the show's genealogist told him that "black sheep often make for the most interesting characters", Gary immediately noted, "Yes, my brother's very interesting." Mainly, the focus here was on two ancestors with very different lives. One, James Pratt, was a serial animal thief in the 1800s ("I though I was the first poacher in our family"), the other, a legal stationer who was educated courtesy of a generous benefactor. A pleasingly Dickensian touch for a man who opened the show walking Partridgely around his mid-renovation west London home with the line: "A chap lived here called Charles Dickens... not that Charles Dickens. You can't have it all, can you?"

This wasn't the most scintillating WDYTYA? of its 10 series, but Gary was value enough ("He's after my crisps," he muttered as a guard as Leicester prison frisked him), even if the ancestry discoveries were probably more of interest to him as anyone else.

For me, as Gary's punditry chums would say, the best value came in a behind-the-scenes sneak at the antiglamour of Match of the Day's Salford studios. A sequence that crescendoed with a shot of Lawro with his legs up on the sofa watching the day's action while Alan "Al" Shearer explained that he spent the previous night eating a lasagne by himself in his room at MediaCity's Holiday Inn. Another hour-long documentary I'd watch, right there.

From Salford to Great Yarmouth and the latest sitcom to extract from the comic mine that is children moving back home to live with their parents. Big Bad World comes from the pens of Lloyd Woolf and Joe Tucker, who tackled similar material on last year's Parents on Sky1, albeit at a generation removed. Whereas Parents saw grown-up Sally Phillips move back in with her kids and retired folks, Big Bad World has Inbetweener Blake Harrison graduating with an MA in Norse literature and finding such a distinguished qualification doesn't always lead straight to a sixty-grand job in the City.

Instead, he's back to Norfolk, living with mum and dad (Caroline Quentin and James Fleet) and hanging around in the pub with his old mates and longing for old flame Lucy (Scarlett Johnson). It's pitched well. I liked the scene when Harrison's Ben applied for a volunteering job abroad and listed his skills as: "Er, essay writing, interpersonal skills... telephony." Fleet's line to his returning son, "Our house is your house, to an extent", was a nice crisp gag, too.

The world of boomerang offspring is obviously ripe for good material – I've liked few sitcoms as much as Emma Fryer's wonderfully melancholic Home Time, which came and went without much noise in 2009 – but Big Bad World isn't quite as immediately as sad and funny as that. But with a bit of time and space, like a boomerang kid, it could find its place in the world.

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