Had incentive to rework English opera (5,2,6)
I believe the answer is:
death in venice
'opera' is the definition.
(Death in Venice is an opera by Benjamin Britten)
'had incentive to rework english' is the wordplay.
'to rework' is an anagram indicator (I've seen 'reworked' mean this).
'english' becomes 'e' (abbreviation).
'had'+'incentive'='hadincentive'
'hadincentive' with letters rearranged gives 'deathinvenic'.
'deathinvenic'+'e'='DEATH IN VENICE'
(Other definitions for death in venice that I've seen before include "Novel by Thomas Mann" , "Opera by Britten based on a Thomas Mann novella" , "Thomas Mann novella set in Italy" , "Mann wrote it" .)