Want the scruffy pair to go in for a make-up (3,5)
I believe the answer is:
war paint
'a make-up' is the definition.
(I've seen this before)
'want the scruffy pair to go in' is the wordplay.
'the scruffy' indicates an anagram.
'to go in' is an insertion indicator.
'pair' anagrammed gives 'rpai'.
'want' going around 'rpai' is 'WAR-PAINT'.
'for' is the link.
(Other definitions for war paint that I've seen before include "Facial decoration showing hostile intent" , "Make-up (for native Americans?)" , "put on a brave face?" , "what woman may have to face" , "Make-up's required" .)