### Clue: Two characters going after 1 (not Turner) in shop (3,2)
### Answer: RAT ON 
 ### Explanation: Definition: shop
 RA(two letters/characters, abbrev. for "Royal Academician", going after Constable's/solution to 1 across's name) + **reversal of**(… Turner) "not".
Defn: To inform on someone.