12a Credit distribution of endless Sudoku (5) I haven't any letters
19a Clever, retaining line in pottery (5) ??L?T
6d Need sentence added to book flyer (9) B?A???I??
7d Nobleman dead in study? No, just outside (5) L?I??
8d Cell division beginning to mutate? So it is, alarmingly (7) M?T???S