Possible Clues:

• ''Half a loaf is better than . . . . . . .''
• B.A. King would have none of it
• Half a loaf is preferable to this
• If you've got this you can't use your loaf
• Out of 19 down, for instance
• 'Half a loaf is better than .. .....'
• 1 across is better than such a food shortage
• One can't propose toast with this
• You just can't use your loaf if you've got this