Possible Clues:

• He makes capital investment, which may be mad
• There's a Mad one in 'Alice in Wonderland'
• Tea party participant (Alice)
• He could well make a good bowler
• 'The Mad --'
• Mad Carroll character
• There's a Mad one in ''Alice in Wonderland''
• 'Twinkle, twinkle, little bat' singer
• One would be mad to have tea with 14 down
• There's a mad one in 'Alice's Adventures in Wonderland'