zest and juice of 1 lemon
zest and juice of 2 limes
1/4 cup Chelsea Caster Sugar
water

Place all ingredients in a jug.  
Top up with water to make about 2 cups in volume.
Stir well until sugar has dissolved and taste for sweetness.
Pour into moulds and freeze for about 1 hour until semi-set.
Insert an ice-block stick in each and refreeze for another 3 hours or until solid.