Possible Clues:

• Cracked like half the code
• Bonkers; speckled
• Excessive, within the boundaries of decency, and totally bonkers
• Not 10 across, by way of a full stop
• Slightly mad (colloq.)
• Dorothy may be called so eccentric
• Spotted bats
• You'd be mad to get so dashy, perhaps, with Morse
• Rather eccentric
• Feeble-minded