English playwright Ayckbourn (4)
I believe the answer is:
'english playwright ayckbourn' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for alan that I've seen before include "Messrs Ladd and Dukes" , "English name" , "- Bates, - Bennett" , "- Bennett, English dramatist, author" , "A.A. Milne's first name" .)