Possible Clues:

• I must avoid ferocious criminal, need I say
• It's to do with a series of lectures, naturally
• Son securing weight with back of foot on treadle-operated machine
• Certainly not on track, with one of the two fellows missing
• 'Sure!'
• On the wrong track one fellow gets lost - as you would expect
• Certainly, without doubt
• Naturally, as one would expect
• Mostly away from the beaten track? Definitely
• Naturally, goes without saying