There is usually some international element in big UK festivals, the old style Sidmouth did and Chippenham have at least one team who live in the UK but display dances from their 'native' (what's the word I want, they may have been born here?) land.
Irish set dancing has been taken up by English dancers too. (Les, we sometimes dance it in Chorlton-cum-Hardy).
It came from France as quadrilles, evolved into English dances (Yorkshire square etc) American squares, and Irish sets, now we are learning each other's.
And the Irish bands that came to Manchester had been on an exchange with a mid- European band, some interesting tunes crept into their playing.