I've heard of the school offering students to stay after school to study if they can't do it at home. I know there's loads of lunchtime study sessions and clubs.
The school does help a lot with uni applications especially oxbridge. We get given mock interviews (stem subjects like engineering are very popular because most students are stem so you will defo get an interview focused on that). They also help with personal statements. The school offers a lot of extracurriculars to boost applications. I know they also do LNAT prep sessions for law that start around December.
I'm not sure about boarding specifically because I'm not a boarder but Wednesday and Tuesday afternoons we're given free time to do an enrichment, the school offers some enrichment courses but also other activities like work experience.