Dined in brassiere at Enfield (5)
I believe the answer is:
eaten
'dined' is the definition.
(having had a meal)
'in brassiere at enfield' is the wordplay.
'in' indicates a hidden word.
'EATEN' can be found hidden inside 'brassiere at enfield'.
(Other definitions for eaten that I've seen before include "What's taken in" , "Polished off" , "having been fed?" , "Got" , "dined" .)