Possible Clues:

• Good number raced in frosty conditions, showing lack of awareness
• There's no knowing what bliss this may bring
• Canoeing erratically across river may be considered bliss
• Silly one caring to show lack of knowledge
• Stupidity is one caring stupidly
• Not a valid defence for a Niger con when demolished
• 'Not no wing, by the sound of it (9)'
• 'A blissful not 2, no? (9)'
• One caring terribly about lack of knowledge
• Bliss, it is said