Possible Clues:

• What duffers play, often
• 'One plays them as a matter of course (8,5)'
• Round?
• They make one round, of course, but they're all round
• That's a round, of course (8, 5)
• One round, of course
• All drilled, but only one round, of course
• Complete course for drivers
• Duffer's venue
• A round of golf