Possible Clues:

• Don't worry, it's a short sound
• Just a short one? Don't mention it
• Don't mention it – no thanks required over sum docked
• By no means
• Response to 'Do you mind?'
• It's a pleasure no former volunteer exaggerated
• U-turn from every single time
• Friendly response to 'Do you mind?'
• First off, a measure of the speed coming in by sea from what sounds like a chain of islands - don't mention it?
• You're welcome? Never!