Possible Clues:

• A to Z, e.g
• Characters providing digs?
• The sound of the male alphabet
• All for the male, by the sound of it
• Rector's put in to settle faulty scholarship
• See 15
• Literature's characters in 24 down, then across
• The three longest answers each have 15 unique ones
• Writer's field
• Leonard Cohen mailed them, perhaps