School of exceptional note (4)
I believe the answer is:
eton
'school' is the definition.
(famous UK public school)
'exceptional note' is the wordplay.
'exceptional' is an anagram indicator.
'note' with letters rearranged gives 'ETON'.
'of' is the link.
(Other definitions for eton that I've seen before include "British public school of note" , "Public school, established in 1440" , "Berkshire public school" , "Note sent up to English public school" , "Public school founded by Henry VI" .)