Question about British boarding schools

[Carol]

I have a qestion about British coed boarding schools with a
Hogwartslike house system. Do the boys and girls from a particular
house share a common room but have separate dormitories, as in the HP
books? Could a couple of teenagers like Ron and Lavender publicly
"snog" in a real British school common room, with no adult supervision
(only the prefects, who in this case say nothing since Ron himself is
a prefect)? I realize there's nothing morally wrong with their
behavior, but whatever happened to discretion and respect for the
wishes of people who don't want to witness public displays of
affection? Then again, matters might become even more, erm,
complicated, if they found some privacy. (In the HP books, boys can't
enter the girls' dormitiories, but there's nothing to keep girls from
entering the boys' rooms, as Hermione does on several occasions.)

Without passing moral judgments of any kind, this strikes me as a
potentially dangerous situation (the possibility of teenage
pregnancy). Just wondering how these arrangements and conditions
compare with real British coed boarding schools with house systems and
what kinds of precautions are taken in such schools, magical
staircases being out of the question.

Carol, hoping that no one will judge her for considering teenage
pregnancy undesirable and just asking for information regarding real
schools