Possible Clues:

• Island once shown by name? It is back in maps
• Incomplete map collection somehow isn't showing ancient continent
• Water world?
• Fictitious place in book about redistribution of tin
• Water world? (... first two letters)
• City lost, in last resort accepting opponent
• Fabulous island finally ejects saint and isn't converted
• Not, after disappearance of old, island seen in maps
• Fabulous place TV department reviewed in maps
• #5