Poggle, I think we'll have to agree to differ.
Yes though, I do know children at both schools and have kids at Haggerston.
Sadly, I personally know two children who have left Mossbourne due to stress and have heard of more. Obviously I don't have stats, but it's pretty well known that lots move - in the early years especially. To give an example, a friend's DD started at Easter in yr8; on her first day, she was one of 6 new kids. For the places to be available, that means 6 kid have left. I doubt they all just moved house!
There's a theory locally, that one way Mossbourne get their results, is to filter out the kids who don't fit their mould, then bring in ones that do. Obviously there's always a waiting list, as a lot of parents want the high results, etc. They are canny too about bringing in the right kids - the rowing 'scholarship' is an obvious example. It's great that kids get a chance to row - I'm not disputing that at all, but it's also a clever way of bringing in more high achieving kids. I think it's 20 kids who can get in via the rowing 'scholarship' in year 9. Three kids were accepted from my son's school and surprise, surprise, all were bright academically. One of them, told me that quite a few of the others, were from private schools, like Forest. So that's 20 new kids, who are highly likely to go on to get storming GCSE results and add to the school stats. It's clever really, but sad for the other local schools, as Mossbourne's taking some of their brightest kids.
As I've said before though, I really don't have a problem with Mossbourne - they're transparent about the way they work and I know lots of parents approve of it. I know kids who are there and fine, so it does work for some and that's great. My only real point is that it definitely doesn't suit all.
Obviously the reason I posted initially was to defend Haggerston, as the way you talked of it was so dismissive and critical and that's honestly not how we've found it. I'm sorry if that was your experience though.