Possible Clues:

• Dire commercial jingle
• Unfavourable - red vase (anag)
• Contrary commercial composition
• Poor publicity jingle?
• Day spent immersed in a bit of poetry is hardly favourable
• A fourth-rate poem, getting such criticism?
• Unfavourable or commercial part of a poet's output?
• Doggerel bishop dismissed as harmful
• Red vase (anag.)
• Unfavourable or harmful, perhaps criticism