Possible Clues:

• Girl to wed, having given heart away
• See 15
• 'Practically perfect' Poppins
• Dame __, historian whose works include Pompeii: The Life of a Roman Town (2008)
• Woman sends back Yankee butter
• With 43 Across, Supporting Actress (''Melvin and Howard'')
• Nickname given to the first public electric steam turbine in the US
• Monarch before Elizabeth I
• See 9
• 'Quite contrary' gardener