Completed fitting, and not before time (7)
I believe the answer is:
overdue
'not before time' is the definition.
(after time)
'completed fitting' is the wordplay.
'completed' becomes 'over' ('over' can be a synonym of 'completed').
'fitting' becomes 'due'.
'over'+'due'='OVERDUE'
'and' acts as a link.
(Other definitions for overdue that I've seen before include "Past the ETA" , "(Of library books) late" , "Still unpaid" , "Not paid at the scheduled time" , "Past the appointed date for payment" .)