I think the school got to give preferences, but were ultimately allocated UCL. That was before she was invited, but after the first boy had been invited, I think. I know when they looked at the other options, both she and he fancied the one in Oxford, but no, they had no say in it
They were put into small groups, 6 perhaps? She wasn't with the boy from her school, and the teachers are whisked away to do teacher-y stuff too. No options on the day either. Obviously the talks were to all of them together - I don't know how many that was! - and then the tour was her small group with a current student, so they had lots of time to chat and ask questions.
I don't think it has changed anything for her, but she definitely enjoyed the chance to have an interesting day out, see the university, broaden the horizons a bit
Has your dc been invited? Well done