My son is in yr 8 at chb so I can help with some of these questions....
There is a transition day in june. When my son went the green bus was free that day for those on induction day which was a great way to try it out, although my son decided on public transport buses when he started in sept to give him some timing flexibility.
At the beginning of the summer holidays chb did an activites week, mostly sport but some art etc. This was great for the children to meet each other.
My son loves sport and has taken part in school teams (he had never played rugby before but is in the A team - there are 4 teams as far as I can tell). There are house competitions in all sorts of stuff sporty or otherwise. Although they don't do football there is a football house tournament.
Homework in yr 7 was very manageable. We/my son had expected loads but it didn't seem much. Sometimes it was to finish off questions he'd been set in lesson but he worked quite diligently in the lesson so ended up with no homework. my son has managed to keep up with all his outside school activities..... although xbox time seems to have diminished!
Judging from parentpay spending my son has some breakfast in the canteen!
I don't get the impression of it being an exam factory, there are so many extra-curricular activities, mostly at lunchtimes although rugby team practice is after school. I feel from my son the expectation is to put effort in.
Overall my son loves it there.