Two characters going after 1 (not Turner) in shop (3,2)
I believe the answer is:
rat on
'shop' is the definition.
(both can mean to betray or inform upon)
'two characters going after 1 not turner' is the wordplay.
'two characters going' becomes 'r' (I can't justify this - if you can you should give a lot more credence to this answer).
'after' is a charade indicator (letters next to each other).
'r' becomes 'a' (both can mean one).
'turner' indicates an anagram (letters must turn into another order).
'not' with letters rearranged gives 'ton'.
'r'+'a'+'ton'='RAT ON'
'in' acts as a link.
(Other definitions for rat on that I've seen before include "Give away" , "grass up" , "Betray" , "desert" , "shop" .)