Most of the muslims apart from the teacher and Leah's friend struck me as interchangeable nonentities. The white characters were more like real human beings, apart from Leah's father who appeared to be a stage villain.The programme did not juxtapose Islam with Christianity because with her background it appeared Leah had no real access to Christianity. In the situation she was in, Islam appeared to be the only source of stability.
Of course it was an artificial situation, if she had been elsewhere, she would have become a Jehovah's Witness, a Scientologist or a Wiccan... the question is only who shows up first to provide the guidance her mother is unable to provide.
This, in essence serves as a warning. Nature abhors a vacuum and if we stand back and, whether through postmodern irony or thoroughly modern fecklessness fail to provide the proper guidance our children need, then someone else will, whether it's Miss Jean Brodie, Osama bin Laden, or Gary Glitter.