Diocesan church had claret distributed (9)
I believe the answer is:
cathedral
'diocesan church' is the definition.
(I've seen this before)
'had claret distributed' is the wordplay.
'distributed' indicates an anagram.
'had'+'claret'='hadclaret'
'hadclaret' anagrammed gives 'CATHEDRAL'.
(Other definitions for cathedral that I've seen before include "Principal church of see" , "St Paul's or St Patrick's" , "See 3" , "place of religion" , "See 6" .)