Oh just remembered I came here to talk about schools. Remember my opinion is tainted by growing up in the SE, and teaching here, and in fact training to teach here.
Primary schools- if you are a half decent parent, the only thing that matters is that your dc is happy there. Forget the academic side, it's very easy to support that at home by reading reading reading reading all the time. It really is that simple. No kids are that bad an influence on your kids before the age of 11 because they don't really get a chance to influence them, so 'roughness' (for want of a better word) shouldn't be a problem. Just ensuring that a primary school fits your child's personality is much more important than what Ofsted say. Some kids thrive in tiny schools, some don't. You'll know well enough by then. I agree though, only send to prep school if you know for certain that you'll send them private for secondary as well, I've never seen a 100% successful move from prep to comp. similar story actually from any 'alternative' schooling at primary transitioning to secondary comprehensive.
Secondary schools are a minefield. Look carefully at how your child will be travelling to school as much as anything else. They will be influenced by kids on the bus as much, if not more, than those in their classes. We live in a nice village, with a very small number of 'rough' teenagers. All those teenagers go to one comp, which is actually very good, and in different circumstances I would send dd there. But I don't want her getting that bus, and I don't want her to be the kid whose mum won't let her get the bus.
If you have a child with learning difficulties, or who is less able, or who is entitled to free school meals, I truly believe the best place for them is the local comp. mostly, they will be in classes as small as in a private school, with substantially better teaching (remember, many teachers in private school have no teaching quals). My DH went to boarding school, he is of average ability academically, and I think it was the worst move possible. If he'd had help with literacy, and had the opportunity to do more practical subjects, he would have done much better than being in a school where traditional academic subjects are pushed and all others ignored. He should have been a plumber or an electrician, not tried to get into banking. He's alright now but his confidence is still shot to pieces from being the 'thick' one (he's not at all!)
Girls do better academically at girls schools. I went to a selective state girls school. We were completely obsessed with boys, sometimes to the detriment of all other things. More eating disorders, self harming, anxiety and stress than you would ever imagine. That might have been because of the pressure of academia as much as anything else, I don't know. That says, if dd turns out to be a certain kind of girl, I'll probably try to get her in to one.
I genuinely believe though, that if you've got a local comprehensive which is Ofsted good or outstanding, that is absolutely the best place for most children. But then, as my FIL has pointed out, I'm a dangerous lefty type...