Possible Clues:

• Cab storage site
• Loudly complain, rep plonked contents here?
• Graves, etc, found here in underground chamber
• Graves may be found below ground here
• Drink stock
• Graves may be found below ground level here
• Store for burgundy etc
• Underground location? Graves may be found here
• Get the Champagne there after a victory, and race back around the Spanish pound
• Underground spot for a cab?