Possible Clues:

• General in command in Northern Ireland going back to Ulster to an assumed identity
• Gin and tonic mixed with nothing is unrecognisable
• Noticing nothing amiss when in disguise
• Disguised one new tooth into another
• Minor member in pub taking it round in disguise
• With concealed identity
• Covertly
• How some agents travel
• Noticing love assignation under assumed names
• Stirring gin and tonic round, under another name