Possible Clues:

• Note returned ever and again, interrupted by another
• 2 minims/4 crotchets
• Note house key always needs to be returned
• Note this is a little half brother to the First Lady
• Musical note
• Note that this may be the little half-brother of the First Lady
• Note that is half-brother to Eve
• Note with part of speech I'm turning up in bishop's office
• Note that this may have been the little half-brother of 21 across
• Note house key always is to be returned