Completed short composition for two later than expected (7)
I believe the answer is:
overdue
'later than expected' is the definition.
(I've seen this before)
'completed short composition for two' is the wordplay.
'completed' becomes 'over' ('over' can be a synonym of 'completed').
'short' means to remove the last letter.
'composition for two' becomes 'duet' (I've seen this before).
'duet' with its last letter removed is 'due'.
'over'+'due'='OVERDUE'
(Other definitions for overdue that I've seen before include "Past the expected time of arrival" , "Beyond the designated time for payment" , "Late for payment" , "Not having arrived at the expected time" , "Beyond the expected time" .)