Possible Clues:

• Chivalrous warrior of olden times
• Jumping piece
• Dub finale of soundtrack on 'Crazy Thing'
• He was trained in chivalry
• One does not move straight on board, sir
• Man with title that can't go straight
• Dubbed chessman?
• 'Can't go straight on board, Sir (6)'
• Contributor to 10's almost in a knot...
• One does not go straight on board to help the mate