Oh I'm sorry, I thought you'd find it funny. "X my arse" is another British idiom (but "Passival my arse" is novel). Yeah "need your head examining / looking at

Oh I'm sorry, I thought you'd find it funny. "X my arse" is another British idiom (but "Passival my arse" is novel). Yeah "need your head examining / looking at" are both quite common; as you say the online dictionary I linked gives it as a variant and you can confirm via quoted Google search strings that they're used. E.g. headline in a major newspaper in 2019 https://www.mirror.co.uk/news/politics/you-vote-ukip-tomorrow-you-14978652 https://www.mirror.co.uk/news/politics/you-vote-ukip-tomorro... As for whether "need your head examining" or "needs its functionality amending" are related to the examples you're giving, it sounds like you perhaps think more deeply about grammar than I do, but I would tentatively say not. Your examples are "<noun> is <present participle>", whereas "<noun> needs its <noun> <present-participle>" seems different to me.