Place sugar syrup, rum, lime juice and frozen raspberries into a blender. Blend until smooth. Strain mixture through a fine mesh sieve to remove seeds

Rinse blender. Place strained raspberry mixture and ice in blender. Blend until well combined. Pour into 4 cocktail glasses and serve immediately

Combine sugar and water in a small saucepan and bring to the boil over high heat, stirring until sugar dissolves. Boil for 3-4 minutes until slightly syrupy and reduced. Set aside to cool at room temperature until ready to make the daiquiris