I can only speak from the experience I have gained from looking at the schools locally to us, but we looked at 3 schools for our kids - 2 secular and 1 CofE.
Out of the 3 of them, the CofE school was far and away the most inclusive of ALL religions and really embraced the diversity of its pupils, taking the trouble to educate the kids about ALL religions, and not just Christianity. We felt with the two secular schools that they didn't really have any policy at all (which is fair enough if that is what you are looking for) and that the issue was brushed under the carpet a bit.
As Christians ourselves, we chose the CofE school not because it would teach our children Christianity, but because it would also actively teach other religions and help our kids to understand that there are other options out there.
Since my eldest two have been attending the school, they have come home with Diwali Candles, Happy Eid cards and all sorts. The school go out of their way to include families of other faiths and there have been many parents come in to their child's class to talk about different festivals, prepare food with them, why they are celebrating etc etc. It's brilliant
In terms of the Christian education, as a PP said, there is nothing really doctrinal taught beyond the major festivals (Christmas, Easter). There is a strong link with the parish church which really only involves the children attending a service occasionally (eg for harvest festival) and the vicar coming into school now and then for assemblies. The 'Christian' focus is overwhelmingly on values rather than doctrine (truth, courage, love etc) which are common to all the major faiths.
If you are concerned then speak to the school directly and ask them what their policy on religious education is. I'm sure they will be more than happy to answer your questions.
Hope that helps, and good luck!