Possible Clues:

• Characters from literature
• The three longest answers each have 15 unique ones
• eg E G
• The sound of the male alphabet
• They rent out B&B perhaps
• All for the male, by the sound of it
• Rector's put in to settle faulty scholarship
• The eight longest answers in this puzzle each have 13 unique ones
• See 15
• Literature's characters in 24 down, then across