Possible Clues:

• Third largest of the planets, and sea god
• Heavenly body training on bend in English river
• Trident-wielding god of the sea
• New extended-play melody from one of the Planets
• It may come close to Uranus
• Writer going over melody - Holst composed it
• Write up the song of the sea
• God of the planets
• Eighth planet from the Sun
• King of the sea