Possible Clues:

• Island in the Firth of Clyde
• It's off south-west Scotland: except it's east
• Only leader of expedition found on island
• Old PM joining in tributes
• Rothesay is on this Scottish island
• Scottish island is a smasher, we hear
• The Kyles of - - (Clyde)
• Scottish island no more than English
• Black Aussie truck in Scottish island
• The northern part of the Isle of ____ is surrounded by the southern part of the Cowal peninsula