It's never stopped Sky (or FilmFour) from showing the same movie week after week after week. If Channel 4 have got the terrestrial rights to this movie, plus they can show it in high definition (which they can't do on FilmFour), and they know that people are about to go watch the sequel to this movie at the cinema, they will want to show it as often as they can because they know that they will get a lot of people watching it every time.
So many programmes are repeated over and over on Channel Four (the same Shameless episode used to be on two or three times a week) - so why not movies?