Possible Clues:

• Composer needs map to go over city
• Capital of African mountain state suffering setback
• Barge adrift by sharp bend that's on River Sava
• Composer gets street atlas to look up city
• Unknown barge travels into capital
• Composer joins extreme characters back in the capital
• Capital retrospective series in September Gazettes
• New zebra crossing good? Capital
• Knocked back some cucumber gazpacho -- capital!
• Zulu on barge moved around city