Possible Clues:

• Month before it turns up south of an island
• Caribbean island from the Spanish for “ancient”
• Caribbean island, one half of a Commonwealth country
• A gaunt marshal outside institute - the one from the Leeward Islands
• West Indies island north of Guadeloupe
• Island in conflict with island, briefly
• Island south of Barbuda
• Island trying to dispose of seagull droppings? No no
• Not in favour of August, on reflection, in Caribbean location
• Drivers must repress dodgy gut in island