Possible Clues:

• Beau --
• Beau -, P. C. Wren's Foreign Legion novel
• Fictional soldier
• P. C. Wren novel 'Beau ___'
• Motion to a garçon, e.g.
• Beau ---
• Percival C. Wren's ''Beau ---''
• Beau of fiction
• Author Wren's family name
• Christopher Wren's "Beau ---"