Joe —, author of stage plays What the Butler Saw and Entertaining Mr Sloane (5)
I believe the answer is:
orton
(Other definitions for orton that I've seen before include "Joe -, dramatist (Entertaining Mr Sloane)" , "British dramatist Joe, noted for black comedies" , "Joe ---, Loot playwright" , "Joe -, English playwright" , "Joe -, Eng. dramatist" .)