Possible Clues:

• Girl who can cast spells? Spooner says it's dull
• What credit (anag.)
• Give up drink that's said to be dull
• What one of the children, as Spooner would have it, is very dull?
• Cook watched it run but it may be still in drain
• Who out of your children (Spooner said) is proverbially dull?
• What something may be as dull as
• Hound's tail, long, thin and proverbially dull