Possible Clues:

• Where it's on to be invoiced, perhaps
• Give voice to 17 down after the tin is in bits
• Sing (prayer) on one note
• Sing on one note
• Sing on there?
• Recite some Latin to neighbours
• Sound of two in the making of nine
• At last one may sing like this under the tin
• Recite, as a prayer
• Sing this in a patriotic sort of way