Banter? None affected 12A 15 (4,6)
I believe the answer is:
Here is my best explanation:
'12a 15' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.
'banter? none affected' is the wordplay.
'affected' indicates anagramming the letters.
'banternone' with letters rearranged gives 'ANNE BRONTE'.
(Another definition for anne bronte that I've seen is "Agnes Grey author, d. 1849".)