Possible Clues:

• 'Oh, that's it! (6)'
• One gets around like this
• Line taken by turbulent cleric
• 'O, that's it in 34 across (6)'
• Shape of a penny
• There's simply no end to it
• To get around the half-century it takes a sorceress
• The never ending round
• Coterie
• Closed, curved line