Seat man arranged for composer (7)
I believe the answer is:
smetana
'for composer' is the definition.
(I've seen this before)
'seat man arranged' is the wordplay.
'arranged' indicates an anagram (letters rearranged).
'seat'+'man'='seatman'
'seatman' anagrammed gives 'SMETANA'.
(Other definitions for smetana that I've seen before include "maker of notes" , "Nineteenth century Czech composer (The Bartered Bride)" , "Composer of The Bartered Bride; eats man (anag.)" , "musician" , "Bedrich ____, composer of "The Bartered Bride" and "The Kiss"" .)