Possible Clues:

• His groundwork makes him comparatively sick at last
• Grain grinder
• The groundwork makes one grand and even sicker
• Dusty food processor has millions comparatively unw ell
• Doing the groundwork makes him more like 21 across at last (6)
• See 24 Down
• All that groundwork may make him more sick of it at last
• "After the Fall" author Arthur
• One gets more than sick at last of the groundwork
• Tropical novelist and playwright