Possible Clues:

• About time male beast replaced companion
• Well-adjusted ship's officer — an Arab, perhaps
• Impasse on board about British colleague in same organization
• One from the same organisation as another
• One from the same organisation
• Draw cover for book for a fellow
• Deadlock involving British chum at one's club?
• One to horse around with?
• Nag firmly established couple
• Horse from the same establishment as another