Just to be clear, this basically would never happen with most people. Now, the North of Ireland (the part still in the UK) might be a little different, but most Irish (i.e. republic) people couldn't give two sh*ts about where you're from as long as you're good craic.
But with headlines like this, and a somewhat-posh English accent, I didn't want to risk either of those 10s: https://m.independent.ie/irish-news/fury-at-torys-call-to-th...
In retrospect it would've been fine, but I had to guess in advance the UK wasn't going to actually try that, and they kinda have a history there…
Nobody gives a fuck.
Now that is an interesting usage.
I take it as using "crack" in an expansive sense of "company" rather than simply "news" or "gossip"?
(Possibly something which may confuse non native speakers of English.)
The spoken "crack" has currency from around Yorkshire / Lancashire north, meaning "news" / "gossip" / "comversation", it'd not be confused.
South of there is isn't so common. Many folks in the northern part recognise the Irishised spelling, but not all.
Have a read of the first paragraph of this, which (as far as GB goes) is a fair summary:
Either that or butt checks, which are also euphemistically someone's "crack", but the implication I took from it being disallowed was the former.