Possible Clues:

• Site around area in Kensington, for one
• Site incorporating a luxurious dwelling
• Somewhat papal, a ceremonial building, impressive
• Area within location for splendid residence
• Site surrounding a bishop's official residence
• What 'mahal' means in Persian
• Potala ___ (Lhasa landmark)
• Royal/official residence
• There's a Winter one in St. Petersburg and a Summer one in Beijing
• Tokyo Imperial ___