Brood raised outside south Surrey town (5)
I believe the answer is:
epsom
'surrey town' is the definition.
(town in Surrey)
'brood raised outside south' is the wordplay.
'brood' becomes 'mope' (I've seen this in another clue).
'raised' shows that the letters should be reversed in order (going up in a down clue).
'outside' means one lot of letters goes inside another.
'south' becomes 'S' (synonyms).
'mope' backwards is 'epom'.
'epom' going around 's' is 'EPSOM'.
(Other definitions for epsom that I've seen before include "Racecourse near London" , "Downs" , "English racecourse" , "Poems about English Derby venue" , "Surrey race course" .)