Possible Clues:

• Stupid clot with poor etiquette
• Procedure or system of rules
• Expert to pass code
• Formal code could be a 24 down in the making
• Poor clot breaks the rules of etiquette
• In favour of getting to Colonel for agreement
• First officer observed formalities
• In favour of having to pass through customs
• Professional to telephone, reportedly, on top of watching Ps and Qs
• Quietly rubbish old army officer etiquette