Possible Clues:

• Knots x 7, then
• Golf score range, with 'the'
• Some time ago morethan half a dozen gets knotted
• More than half a dozen knots of centuries ago
• School uniform matches period in history
• Some time ago they might have been not, by the sound of it, little more than half a dozen
• Over half a dozen knots happen, that is to say, in the ship
• Even in there with the swine they are in the past
• The way to go back thirty years at over six knots?
• Some time ago, at more than half a dozen knots