Possible Clues:

• Opera made to run smoothly if given a boost
• Opera running smoothly, even though held up?
• Opera that inspired the T-shirt slogan
• Beethoven opera; I.e. if old (anag.)
• Heathen spurned in one old opera
• Opera subtitled 'Wedded Love'
• I had accompanied priest into Foreign Office during opera
• Noted performance of chess people putting up work of art
• Opera that includes the 'Prisoners' Chorus'
• I foiled new opera