Possible Clues:

• Lacking adornments
• Severe and strict
• Suet rolls inside are not of luxury type
• Teresa worried about university being spartan
• Severe or strict in attitude
• 'Or sound at the wheel, strictly speaking (7)'
• 'Or be at the helm at the stern, by the sound of it (7)'
• Severe; lacking comforts
• Cold tea sure to refresh
• 'Spartan, simple (7)'