1. Half a quarter in the US. (6)
4. Thoughts about loudly interrupted ballots after a royal launch. (11)
5. As a first class return hides sweet chicken. Who’s sixth? (12)
12. Direct directions for whistler. (7)
13. Sounds like a sea has lost an eye after you were behind a queue of squares? (9)
18. Raise measures (so I hear) to stir up most of the atmosphere after I have left. (7)