The Asian community is not a homogenous one and cannot be easily lumped together, really. And as the majority of primary school pupils in Birmingham are non-white, you are pretty much talking about the majority of parents...
Parents are individuals and presumably make pretty individual choices about school entry.
From the boys I know at CHB and my sons and their friends, they all seem able children, of different temperaments (the school is not full of clones) and nobody is struggling terribly or needing lots of extra tuition.
The school does provide extra support for boys when needed but I am aware that some external tuition does take place, particularly for the sciences, which is the only subject area that I as a parent have found issues with, but no mass tuition is taking place - or any more than would go on in most secondary schools serving a relatively well-off pupil body.
I took a pretty sink-or-swim attitude when my children started KECH.
I had certainly helped them through the primary phase and the 11 Plus prep but as far as I was concerned, they had a good school and they should make the most of it themselves. I told them when they started to make the most of their place as there were plenty of children in the city that would have wanted that place too. An old friend in Manchester told me, when I was working through the 11 Plus with ds1, that this exam was the last one we as parents could ever help with. And I think she was right.
I have a large family and smaller children to focus on and support, which justifies my 'neglect'. Ensuring there is a constant supply of food, that they shower, and that most of the time they have clean games kit, is quite enough to be getting on with.
I do know GS parents who know all their child's classwork and homework, or who cannot rest in the evening until their child's homework has been done and checked by them. I don't know how common this is. Some even vicariously live their child's academic life. Do most GS parents do this? Surely not? I am going to be brutally honest - I could not name all my children's teachers and don't really have a clue what they are doing in the various subjects and certainly have no idea about their homework. I never ask ds1 about his because he appears to always do it. I occasionally ask ds2 about his because from the irate comments in his diary, it appears he doesn't always do it. That said, he has matured and stepped up recently so sometimes time is the answer to a child's intransigence. I only ask dd about her homework if she's not too hormonal that day
. I went to her parents' evening expecting to be told that she was doing awfully and never handed in homework, and was in fact told the opposite, which was quite a surprise. I would honestly recommend to any parents worried about their (secondary age) child's work that ignoring it for a few months may be the best thing they can do.