Greek island — Charlie seen with notes (5)
I believe the answer is:
crete
'greek island' is the definition.
(Crete is a Greek island)
'charlie seen with notes' is the wordplay.
'charlie' becomes 'C' (phonetic alphabet: alpha, bravo, charlie etc.).
'seen with' means one lot of letters go next to another.
'notes' becomes 'rete' (re and te are musical notes as in do-re-mi).
'c'+'rete'='CRETE'
(Other definitions for crete that I've seen before include "Island whose largest city is Heraklion" , "Largest Greek island" , "Large Greek island" , "Herakleion its big port" , "Erect (anag) - Mediterranean island" .)