Possible Clues:

• Piece of music from a shop that's out of place in road close to Piccadilly
• Composition in D sharp originally containing nothing unknown
• "___ in Blue" (Gershwin tune)
• Symphonic form
• Elation
• Elated bliss
• '-- in Blue' (George Gershwin)
• Harps played by group wanting bass for emotional piece
• Emotional musical piece
• Epic poem of perhaps 'Odyssey'