The oldest daughter was in school, as she was offered a place first, when the visit was booked. (So we knew she had to take time out of school for the visit.) As soon as the visit was booked, her school was informed and they said it was ok, as long as we were prepared to take school work with us to do. Of course it was ok. We put it in writing later than the verbal conversation, and before we left.
Thus, when the other 2 started school the school knew that they had a booked visit to see the family.
I trust this clarifies what you asked.
I'm just not too sure why we would be in trouble as the Head said it's ok to go? She surely should have known better, and as she is an authority, we just took her word for it.