Possible Clues:

• Audition of black horse
• Titled man - chessman
• At end of dusk it's dark, man!
• Man who may be white, despite what we hear
• One won't go straight on board when it's dark at last
• Chesspiece (in shining armour?)
• Male honoured by the British sovereign
• King accompanied by dark rider looking for adventure?
• Man on board's short retirement speech heard
• In Britain, a person honoured by the sovereign for personal merit