Possible Clues:

• A shoe size bigger than 9C, say, on conference goer
• Person present and participating, in a meeting perhaps
• One of those from The Gathering to shepherd matinee idols at the centre
• One at a conference
• One present at function two hours before noon departs before middle of speech
• Antonym of ''skipper''
• One in an audience
• Eg, one at a conference
• Nurse in a casual shirt as someone at conference?
• One present late in the morning or evening by river