Grace Dent on Television: Downton Abbey, ITV1

Someone should be getting a proper shag within a 50-mile radius of that house instead of a 55-minute lead-up to a hair ruffle then crying

Marriage à la mode: Downton’s Dan Stevens as Matthew Crawley and Michelle Dockery as Lady Mary (ITV)

There was a time – circa series one of Downton Abbey – when I'd have happily have lived there and clipped about that big house in a feathery hat and uncomfortable corset, clanging my bedside bell for maid service, fretting about war, mourning the Titanic and making Dame Maggie Smith's face curdle with my slapdash fish-knife usage.

Nowadays, I'm not so sure. Downton returned this week for its third series with an arduous extended episode which began just after The X Factor and seemed to continue so long that by the closing titles my eyebrows needed threading.

Series three: war is over, no more Downton convalescent home, no more aristocrats sloshing bed-pans around and wounded servicemen titting up the scullery-maids. Downton last time began to lose me somewhat. Plus that habit of beginning every scene with a character explaining loudly what was going on giving an historical cultural reference to remind dim viewers who normally watch ITV1's Wild at Heart that this is YE OLDEN DAYS was starting to mentally chafe.

Now it's just the family and staff rattling about Downton again, snapping at each other over minor umbrages or petty over-steppings of marks, namely who reports to whom, who is whom's servant, who is actually a servant or a footman or a valet and which guest is bringing a lady's maid, and should the lady's maid be allowed dinner in the kitchen and, oh Jesus Christ, let's all bicker about this for hours in a drab kitchen while someone plays viola.

More annoyingly, Lord Grantham, in light of his youngest daughter Sybil running off with the chauffeur, is now so perilously thin-skinned he should be pushed into Downton's attic and left there for his own mental safety and that of all our ear-drums. At one point I had faith in that man as a "safe pair of hands", mainly based on his way of standing thighs-apart looking authoritative while a servant did his cufflinks – but now Lord Grantham has admitted he's lost the family fortune, I am somewhat less duped by his know-all swagger. I'll forgive the Lord's ire about Lady Sybil, however. For a time, I was wholly pro-Sybil and her stalwart Irish lover Tom. For God's sake, someone should be getting a proper shag within a 50-mile radius of that house instead of a 55-minute lead-up to a hair ruffle then more crying. But when Tom is vertical instead of horizontal, he's just a boorish political blowhard and we're all exhausted by listening to him. Sybil, dump him love, get yourself back to the big house with the delicious breakfast buffet.

Season three opened with preparation for the joyless wedding of the permanently furious Lady Mary – she of the infamous combative vagina which killed a previous suitor who attempted penetration – and foppish dear cousin Matthew, the commoner they've all decided they like more now he's rich.

Truth be told, Matthew sussed in series one that Mary is a terminal whine who aimed to marry him for convenience (Matthew is due to inherit the big house Mary lives in; Mary really likes the big house). Yet, for plot purposes, Matthew has put a pin in this knowledge and is channelling "naive but happy". Their wedding does not move me much. It moves me like an expensive country wedding between two people who I'll give two years tops, which involves me taking a train, then a commuter train, then a pre-booked taxi to a drab B&B, carrying a big George Foreman grill. Matthew and Mary are not star-crossed lovers. I was more emotionally invested in the 2007 MTV show Totally Jodie Marsh: Who'll Take Her Up the Aisle, which was a roller-coaster of emotion resulting in a man in a trilby called Matt agreeing to marry a woman supporting her breast implants with a concho-belt who he claimed to have met four weeks previously. It was like movie love.

Thankfully, someone else who shares my excitement for Matthew and Mary is Shirley MacLaine's character Martha Levison – a brash, forthright American who has come to Downton to tell the truth. This was Maggie Smith's job until now, and I don't think there are enough good lines to go around. The best part of episode one was Martha's American maid appearing in the kitchen to tell "shouty ginger cook" and "sad scullery maid who last series was forced to marry a corpse" of Martha's demands. "She drinks goat's milk. No fats. No crabs. And nothing from the marrow family."

Shouty ginger cook is never very far from a heart murmur anyway. Downstairs, staff Thomas and Sarah are now so evil they should be accompanied by a sneak trombone and theatrical cackle effect every time they walk into shot. This is Parade's End for people whose lips move along with the telly, and who express they like a joke by shouting it loudly back at the screen. I never thought I'd say this, but bring back the bed pans.