Possible Clues:

• Glimpse 'E's hiding the secret agent
• Strangely yes, around a quiet spot
• Catch special insight by unknown character
• Catch sight of a secret agent online?
• Spot pair of specs amongst the elderly retiring
• Notice someone puts up, say, finally
• Notice first sign of estate agent
• The spy is losing this watch
• Catch sight of shapely Hal leaving disguised
• Get a look-in for the agent of the East