I too hope your DD is OK namechanged.
I do not think it is just schools striving for good results though. Lots of pressure from all quarters for some children: eg. that they must fulfil potential, be the best they can, not let themselves down, work hard etc etc. I totally agree that getting the university place is a massive focus, but that can be said for the BBB student as well as the AAA* student. I do think some of the pressure comes from the expectations of parents and some young people are clearly not well equipped for university and find life very difficult when they do not have continual hand-holding and advice. Continually being top at school is not always an indicator of being top at university, particularly if the student has worked exclusively on A Levels, had a lot of input and is not a rounded personality who can cope with what life throws at you at university.
My elder DD did not work that hard at university. She had a great time at Bristol. Others wanted to work much harder but did not get better results. It is important to keep a balanced life and she was lucky in that she appears to be able to work when needed but do other things as well. This is rarely discussed on mumsnet - there is an obsession with first class degrees and all the outcomes I list above. She now has a great job and is working hard. She knows how to work but she also knows how to play and relax to keep healthy. Pushing for the high results, fear of not getting a job and keeping up appearances really does add to stress. It is not vital to be the best but it is vital to be happy.
I agree, bluesky: Bristol has a pretty pathetic Union. Fresher Events are mainly halls based and really not that full-on. There are a few social activities but students do not necessarily do all of them. Bristol University is a place where students do it for themselves because they are in the city and not on a campus miles from anywhere.
I do agree that parents should be involved where students have MH issues but as we know, these are not always evident before the student starts. It is a very adult and savvy group of students who will notice something is wrong with a student they barely know and report it.
I also agree that for some students, a transition year is important. A break from A level pressure, doing a job, cooking, finding hobbies again that were dropped for A levels could all help with mental health and not least, really understanding what is needed at university and how to enjoy it rather than just see it as more pressure.