Get together with a redhead, mate (5)
I believe the answer is:
rally
'get together' is the definition.
(rallying is a kind of getting together)
'with a redhead mate' is the wordplay.
'with' is a charade indicator (letters next to each other).
'a redhead' becomes 'r' (head letter of 'red').
'mate' becomes 'ally' (I've seen this before).
'r'+'ally' is 'RALLY'.
(Other definitions for rally that I've seen before include "Recuperate in gathering" , "several shots" , "Marshal" , "Assemble - recover" , "Arouse for action" .)