Possible Clues:

• Farewell to owing money, Leo has nothing
• Farewell to love in commotion about sign
• Say goodbye to the Lou, perhaps
• It's as well to include large numbers, being short for so long
• ''Ta-ta''
• "Bye-bye!"
• See you later!
• Farewell (old inf.)
• Team-leader led astray in circles for so long!
• It may be said when 15