Possible Clues:

• Taught after school, maybe
• Taught small groups
• What signal does for danger ignored by navy, as instructed
• Rude tot (anag.)
• Gave private lessons to
• Instructed rude tot with difficulty
• Taught one-to-one
• Sound of disapproval at eighteenth letter in dictionary being taught
• Trade union going leftward as instructed
• Get tea with you to ruddy well get some know-how