Oh why the hell we can't just have secular schools and those who want their children to learn about the family religion take classes after the state has had the students for the day...It's how Muslims,Hindus,Sikhs,Jews have managed in this Christian based country for generations.Lets take all faiths including Christianity out of schools and just keep it simple.
The only concession I'd make is that there would be a lesson and exam (compulsary) on each and every faith in the world just so everyone learns about the basics of everyone's faiths and it would be part of the PHSE syllabus.
I'm sorry for any RE teachers but you're out...