Greek letter, recent, on series of items for stamps fan (11)
I believe the answer is:
philatelist
'stamps fan' is the definition.
(philately means stamp collecting)
'greek letter recent on series of items' is the wordplay.
'greek letter' becomes 'phi' (letter from the Greek alphabet).
'recent' becomes 'late' (similar in meaning).
'on' is a charade indicator (letters next to each other).
'series of items' becomes 'list' (I've seen this in another clue).
'phi'+'late'+'list'='PHILATELIST'
'for' is the link.
(Other definitions for philatelist that I've seen before include "Person with hobby" , "Stamp collector" .)