"Round the twist"... what's that all about?
In my industry, aviation, we've a lot ex-pat Brits. Which is an opportunity to segue to the fact that, at one time, I used to explain many U.S. colloquialisms by referencing the numerous "parts of the country" from which juxtapositions and accents derive. I don't use that excuse much anymore since exposure to the ex-pats (plus Australians, New Zealanders, Irishmen, Scotsmen, etc.) have taught me the error of my ways.
Many of the "newly developing" irritating Americanisms do emanate from succeeding generations though. These can be just as unintelligible and grating to my ear as asking a bayou born and bred Louisianian or a newly arrived Dublinite to slow down in their speech, to be given time to be understood.
Most younger citizens cannot complete a sentence without interjections such as "dontchakno?", "yaknow" or the worst of all time... "he/she goes" (deciphered as "he/she says or said". But my guess is that these are just as much an epidemic in the U.K. as they are here in the U.S.
(What's with your use of ladybird (ladybug... the orange-black spotted ones, dontchakno?)
After-after thought... our President and many others are now using "Give a shout-out to..." when, supposedly, meaning give praise to... Where'd that come from?