QI once told me that “England” was once generically used interchangeably with “Great Britain” and that our modern separation of the two is, IIRC, a 20th century invention. No idea if it’s true though.Many English people have the habit of saying 'England' when they really mean Britain. I used to pull people up on it. Can't be bothered nowadays. Don't pull up anyone not from Britain. Don't expect them to know or necessarily care that there is a difference.