When last we left the Crawleys and their minions at Downton Abbey, love had triumphed upstairs and downstairs.

Ladies Edith and Mary were married, Mr and Mrs Bates were parents, and Lord Grantham was pleased with himself.

That peak happiness continues in the family’s beautifully preserved world of nostalgia and privilege thanks to Focus Features’ Downton Abbey movie, which picks up seven years on from the beloved TV show.

Downton Abbey has always been about loyalty and tradition, and both are writ large in the film. It would best be viewed not at the cinema but on a Sunday night couch, nursing a sherry and low expectations of anything but a delicious burst of decadence.

The opening scene sees the Crawleys receiving news Downton will host a visit from King George V and Queen Mary.

Michelle Dockery, Elizabeth McGovern and Laura Carmichael put their best satin-buckled feet forward in Downton Abbey. Photo: Focus Features

They take it with the enthusiasm akin to hearing the junior footman needs the afternoon off to have a boil lanced.

It’s all a bit of a bore really, what with all that silver to polish.

As Lady Mary (Michelle Dockery) sighs while her lady’s maid Anna waits on her, “It’s all just such a struggle.”

The staff, however, are mostly aflutter with their desire to make Downton look anything but a provincial operation.

Royalty! Pass the smelling salts, crack out the state livery and let’s get those extravagant set pieces on the road.

The point of the film is to bring back the luxury of 1920s aristocratic England – sun-drenched golden walls, brandy glugging into crystal – to those who have pined for it since the curtain came down on the TV show in 2015, and it does that in spades.

The dowager countess (Maggie Smith) is the pithy heart, her relentless pursed-lip zingers the energetic counterbalance to everyone else’s insouciance. She even finds a new nemesis, the Queen’s lady-in-waiting (Imelda Staunton), with whom to test her mettle.

Of course the fashion is fabulous. Watch for Mary’s show-stopping silver and black gown and Edith’s (Laura Carmichael) pale-peach lingerie, the sexiest thing she’s ever worn.

What’s missing is the brawny soap opera melodrama.

The movie treats its central figures as caricatures and sees them blithely rocketing from a gravely violent incident to afternoon tea with a princess.

The disquiet Edith feels after trading an independent London life to become Marquess of Hexham is glided over before she goes back to smiling like a loon and worrying about gowns.

Her stilted husband Herbert (Harry Hadden-Paton) is the only character in the movie less appealing than the relentlessly insipid Cora (Elizabeth McGovern).

Black sheep son-in-law Tom (Allen Leech) does his country a service and is plunged into an unlikely alliance that could change the fortunes of the Crawleys but still seems like window dressing.

The servants, whose travails have long been meatier than their employers, devolve into capers more like French farce than period drama. It’s amusing in pantomime fashion but oddly unworthy of the franchise.

Mr Bates (Brendan Coyle) and wife Anna (Joanne Froggatt) have a moment. Photo: Focus Features

Roped back as butler, Mr Carson (Jim Carter) is again more lordly than his actual milquetoast milord (Hugh Bonneville.) Kevin Doyle as servant Molesley nearly steals the show in a scene where he is so excited he yells across the dining room at the King.

Black hat Thomas Barrow (Rob James-Collier) has lost his fangs, his trademark scheming replaced by a gay romance storyline that is both uplifting and so sentimental it’s almost loopy.

That the Crawleys’ lives appear preserved in aspic is probably the point.

There are no surprises other than a scene where the waspish Mary takes life advice from the hired help like a docile lamb.

Mary has always been Downton’s great conundrum – is she a classic mean girl or is her arch willfulness wonderful? – and she’s the same here, sighing over whether to sell the estate, deciding not to, and whirling untouched into the next ballroom.

That said, Dockery shares the film’s most genuinely affecting moment with her granny. It takes Downton back to the theme of love, for family, tradition, honour, duty.

Violet Crawley (Maggie Smith) melts ice queen Mary (Dockery.) Photo: Focus Features

Director Michael Engler and writer Julian Fellowes (whose 2001 Gosford Park was a much more compelling period movie) have dished up something with an appealing silliness but the gravitas of a souffle.

The question is whether the entitled Crawleys deserve our devotion just because they’re familiar.

Downton Abbey is like 2008’s Sex and the City film: Unnecessary but true enough to its characters to keep fans happy.

Downton Abbey screens nationally from September 12