Possible Clues:

• Allowed to carry thin glove
• Challenge, symbolically
• Baking a gluten tart initially is a challenge
• It's thrown down in challenges
• See 22 Across
• Finally visiting relative, allowed protective clothing
• Handy thing to take up or run?
• Grand relative permitted glove
• Part of a duelist's uniform
• Indication of challenge that may be punishing for runner