Is that it? Seriously? A few cups of tea and some scones at a cricket match and that's what you're going to leave us with? This was a giant serving of anti-climax, dolloped out with bouillon spoons.

There was no obvious cliff-hanger. Thomas was going and then he wasn't and then he was and then he wasn't. There was the bizarre introduction of a new character who went nowhere (Rose). And we had only a tantalising sniff of Her Ladyship's soap. Too fleeting! Seasoned, jaded viewers who have stuck with this sequinned turkey of a series through burnt kidney souffles, the death throes of eclampsia and tingle-free impotence deserved more, far more, than Molesley and his sticky wicket.

There was something of a literary sheen to tonight's series finale, however. Miss O'Brien was referencing Oscar Wilde. The costume department was channelling Brideshead Revisited. And there was a frenzied depiction of something that can only be described as Fifty Shades of Bates.

We zoomed in on Bates several times with various soft focus, Vaseline-lens shots. See how he collapses, winded, on to the sofa! See how the drops of paint splash on to his face as he does his manly home-decorating! We had a real, gruff, Mellors line of dialogue: "You being in the room is enough to make it nice. Come here." Bates fans might have needed to be locked in the cold meat cupboard to cool down.

I rather loved the decadent scenes in the Blue Dragon, and Rose, the flighty, young, blonde Helena Bonham Carter. But she felt like a refugee from the decommissioned Upstairs Downstairs. What was her presence supposed to signal? Other than, "You'd better give us at least one more series."

And as for the gentleman editor (who looks exactly like Edith's previous doomed suitor) with his Mrs Rochester lunatic wife ... Couldn't we at least have waited a bit longer to find that out? Still, excellent use of "telephone as Wikipedia" from Edith.

The costumes deserve special mention in tonight's episode, especially Cora's embroidered number and the lilac colour palette. But so frequently the painstakingly recreated aesthetic of the series has only served to point up the weaknesses in the plot.

Most disappointing thing tonight? A complete absence of Isis. She would have loved the cricket! She was obviously being punished for stealing every scene last week. And the most delicious irony of all? The gentleman editor's explanation of his wife's condition. "A lunatic is not deemed the innocent or guilty party ..." And once you're involved, you're simply tied to the madness and unable to escape. Heavens. It's just like being a Downton viewer.

Random subplot alert

Mary and Matthew's failure to secure the succession is becoming tedious. And the mention of the "little prince" was toe-curling. "Now we can start making babies." Haven't they said essentially the same thing every episode for the past eight weeks? As has been noted many times in the comments on this blog, they have gone from the hottest couple in Christendom to lacklustre and chummy. Maybe that's aristo marriage for you.

How did Mary manage to go off and have an operation without anyone noticing, by the way? And why are we spared the details of the mysterious procedure when we were forced to endure every cramp and whimper of Sybil's womb? Plus, as usual, the whole business was discussed as if we were sitting on Oprah Winfrey's sofa: "I'm not sure blame is a very useful concept in this area." I'm still waiting for Mr Pamuk to have a hand in all this. And my only hope for future series is that he will return to haunt us – and Mary – in some way. Come back, Kemal, all is forgiven!

Golden eyebrow award of the week – and the series

Carson's consideration of Thomas' "condition" caused mammoth eyebrow action of the most impressive order. "I cannot hide that I find your situation revolting. You have been made by nature into something foul." I cannot hide that I find it unlikely that in a 1920s household so many people would have 21st century insights into sexuality ... But never mind.

And just when you thought the butler's brow couldn't jump any further off his forehead, the Earl of Grantham went ahead and promoted Jimmy to first footman without so much of a by-your-leave. "What?!" harrumphed Carson.

And so – please sound the fanfare – the Golden Eyebrow goes to Carson for a third time, crowning him Golden Eyebrow Series winner. A pair of gold-plated tweezers will be making their way to the offices of the theatrical agent of Jim Carter. Or if I can't find any, I will make some out of cardboard and paint them with gold nail varnish. No expense spared for this accolade.

Surprise character development

Suddenly the whole denouement of the entire series is supposed to depend on the fact that suddenly Alfred grows a backbone? Oh, come on. The whole business with Thomas became too complicated, despite brilliant performances from Rob James-Collier and Siobhan Finneran. One minute Carson's going to make Thomas sorry. Then Jimmy is. Then Alfred is. In the end, everyone ended up being promoted apart from Bates. And we never got to witness Thomas's face in triumph, which would have been a picture.

Once again, the Oprah-style understanding of Thomas's "situation" seemed completely anachronistic. Although it was worth it for the earl's priceless line: "If I shouted blue murder every time someone tried to kiss me at Eton, I'd be hoarse within a month." Too. Much. Information. Note: Uncle Julian was not educated at Eton but at Ampleforth. So this might have been a bit of a dig.

Sorry, could you just repeat that awkward line of dialogue?

Cousin Violet: "The thing is to keep smiling. And never look as if you disapprove." That's right, Cousin Violet. You could never look as if you disapprove.

Matthew: "Married men who wish to seduce young women always have horrid wives." So true.

Edith: "I find the idea of a married man flirting with me wholly repugnant." Er, you didn't say that when you were cosying up to the farmhand in series two.