Was down south to find vehicles (6)
I believe the answer is:
mopeds
'vehicles' is the definition.
(moped is a kind of vehicle)
'was down south' is the wordplay.
'was down' becomes 'moped' (to mope is to be sad or down).
'south' becomes 'S' (synonyms).
'moped'+'s'='MOPEDS'
'to find' is the link.
(Other definitions for mopeds that I've seen before include "Lightweight motorcycles" , "Light motor cycles" , "Low-powered motor-cycles" , "bikes" , "Low-powered motorbike" .)