Possible Clues:

• Remove seat from (a horse)
• Used Land Rover to take gear from Arabian
• Be successful at a joust
• Allow to go bareback
• Dislodge from seat in organisation in stable environment
• Peacekeeper meets theologian to make a deal to remove the rider?
• Peacekeeper meets theologian in deal to remove the rider?
• Unstable land used to shift from mount
• Dislodge a horse rider from their seat
• Forcibly dismount someone