This list has been mentioned on other threads, but I thought it probably merits its own thread as a resource for parents looking for suitable boarding schools.
Noting that this list includes only co-ed schools, and so many leading schools are excluded. Still useful, I hope.
https://www.best-schools.co.uk/uk-school-league-tables/list-of-league-tables/top-100-co-ed-boarding-schools-by-a-level