'The Aroma of Those Niffy White Flowers'

I’m inhaling Right Ho, Jeeves (1934), P.G. Wodehouse’s second novel devoted to Bertie Wooster and his titular valet, and came upon further evidence that speakers of American English and English English don’t always share a common tongue. Bertie observes: “The garden was full of the aroma of those niffy white flowers.” Niffy? Close to sniffy but what does it mean? Fragrant or noisome? The OED identifies it as “British colloquial” and promptly answers my questions: “Having a strong smell, esp. an unpleasant one.” The context is worth quoting for the full Wodehousian touch:

“What with all this daylight-saving stuff, we had hit the great open spaces at a moment when twilight had not yet begun to cheese it in favour of the shades of night. There was a fag-end of sunset still functioning. Stars were beginning to peep out, bats were fooling round, the garden was full of the aroma of those niffy white flowers which only start to put in their heavy work at the end of the day--in short, the glimmering landscape was fading on the sight and all the air held a solemn stillness . . .”

That tone is unmatchable and unmistakable. Trying to imitate Wodehouse is fatal. Back to niffy: Do any readers in England know the word or casually use it? The OED also gives niff as a verb – “To emit an odour or smell, esp. an unpleasant one; to stink” -- and a noun – “a smell, esp. a disagreeable one.” The word’s origin is “uncertain,” though the Dictionary suggests it may be related to sniff or whiff. And here’s a bonus: Wodehouse used a variant of niffy in another novel, one I haven’t read, titled Money in the Bank (1942): “Anyway, Stinker, putting aside for the moment the question of your niffiness, wasn’t it notorious that you couldn’t tell the truth?”