Possible Clues:

• I agree with you (sigh!)
• Positive response repellent in fringes of Hackney?
• 'Yup!'
• Grass given up, newer drug taken, in casual agreement
• Yes-man comes back over exclamation
• Okay
• Positive reply
• Man associated with comets, missing Central Line once or twice, returns quite casually
• Encouraging word
• Karen O?