Certainly no nurturing or quiet encouragement to try out for things or leave your comfort zone
Sorry you're feeling this way. This is the opposite to my experience as a parent. My son is at LU. The list of clubs and societies is staggering and students create new ones all the time. I don't see how anyone can be left out. I know some students who are never busy outside lessons, but it's always out of choice according to their parents. My son came from a estate school and has hardly ever had a free lunch period plus most days he stays after school. But that has always been his choice.
After several years in the school I can confirm that the idea that most kids participating in plays, orchestras and A teams are the privately educated ones is simply not true.
In terms of how competitive it is to take part in plays, music, teams, etc, there is selection for sports teams (A-E), but this happens in very school I know, and it's only logical if you want to ever win a match. In the lower school both girls and boys choirs are open access without audition. The standard for the lower orchestra I believe is only grade 3. Year 7 have their own play for which there used to be no audition, I'm not sure if that has changed, but the pool is smaller and not everyone will want to be on stage. There are numerous plays during the year requiring audition, some involve the whole school, others will be for the middle school or the sixth form. If you are the type that either gets a main role or sulks and feels frustrated, then yes, you're in for a disappointment (or not). But I know kids who have been in every single play with tiny roles, or just as backup dancers, or even as technicians, and have loved the experience and had a blast, and there are many of them. Again, you're not competing with the whole school at audition. So many students do not want to be on stage at all because they are just into other stuff. The drama department just ask one thing from everyone: commitment. The kids that land main roles are not only talented but they show up, learn their lines, go the extra mile.
Personally, I feel the school has been a blessing for DS. He had no wobbles and felt at home from the start. He made a group of friends who have remained his friends to this day. They don't party although I know some do. Maybe he was just a good fit for the school. If there is something that has always stood out for me is his relationship with his teachers. Teachers at LU like to be challenged and the school encourages free thinking so students get used to speaking their minds. In my conversations with teachers, they appreciate a student that is a "partner in learning" rather than just an obedient, compliant note taker. Individuality is very much fostered and DS has never been made to feel he could not dispute or call into question something.
It's not a school for those seeking the old British public school flavour of bygone times. There's no house system for example. Plays can be more explicit than in other schools and tackle issues others may want to push aside (believing you can shelter children from reality these days, which is a delusion). To me, that makes it a school for the XXI century and that's the century our children are going to have to sail through.
Jesus this was long.