Possible Clues:

• Rubbernecker
• One with a wide-open mouth
• Slack-jawed one
• Mollusc that has one looking amazed?
• Takes a longer look at middle-age primate near castle
• One staring into space about to make a comeback
• Mollusc to get one staring
• Wowed eyewitness
• One staring at space hesitantly
• Georgia's an easy catch