Bring the sugar, water, oranges, lemon, cinnamon, bay leaves and the mint to the boil and cook for 15-20 minutes. Cool.
When cool, pass through a fine sieve into a clean container.
Add the grapefruit juice and some finely diced mint leaves. Take approximately ⅓ of the syrup and put into ice cream machine. Just as this is setting whip one egg white and fold into sorbet. Complete