I have a nephew who went to Gordonstoun summer school last year. She learned English courses and took part in lots of outdoor activities. she really improved a lot in English speaking and became initiative. i really felt surprised.
are you looking for individual or summer tour? If individual, I know that some boarding do offer summer program, such as harrow school offer a international summer piano academy, roedean also offer some summer programs with different kinds of sports or academic subjects
I am looking for summer program me for secondary students, do those schools normally lend out the campus for summer school or summer schools are normally organized by schools themselves?