Well locally our church is covering 15 schools so far, so actually I don't think it is that big a deal for churches to do. If you are part of a denomination I would expect that there is someone who has already been working on this at some level. Again our experience isn't that it is the material that is important, but actually it is the qualities of those teaching it.
Doodle2U hasn't really given any detail about the proposals as far as I can see on this thread, though this isn't the first thread on this topic! What she has indicated though is that it will still be down to individual schools as to how they want to implement programmes such as these, and ime they are eager for people to partner them in that.
In terms of educating your children early, yes, I really think you must. If you keep them ignorant, then even if SRE was banned from schools, they would still learn about sex and relationships at school, as well as when they are reading, watching television, out and about and seeing billboards or advertising. Your family is the main model of family life, your relationship with your dh will be the most informative one to your dcs. Personally I think that you equip children better by educating them rather than keeping them in ignorance. There is plenty of Christian material aimed at young children.
If you have concerns about how things are being taught, then engage with the school, volunteer and support it. Become a governor and then you have a vote on how such measures are adopted or implemented. From your rants here I think that you are showing your ignorance of how schools operate tbh.