Bar set up in Benidorm (3)
I believe the answer is:
rod
'bar' is the definition.
(I've seen this in other clues)
'set up in benidorm' is the wordplay.
'set up' says the letters should be written backwards.
'in' indicates the answer is hidden within the clue.
'dor' is hidden within 'benidorm'.
'dor' written backwards gives 'ROD'.
(Other definitions for rod that I've seen before include "Imperial measure" , "See 13" , "Fishing implement" , "A few yards" , "Former measure equal to a quarter of a chain" .)