Boil cumquats in a large saucepan of salted water for two minutes and drain. Bring castor sugar and water to the boil and add cumquats. Cover with greaseproof paper and simmer for 30-40 minutes or until soft and skin is translucent and shiny. Remove from heat and allow to cool. Once cool, use a small knife to remove pips without cutting into cumquats too much. Reserve in the syrup. Pre-heat oven to 170C. Make custard by mixing eggs, milk, cream and ½ cup cumquat syrup. Lightly butter bread and cut into triangles. Layer a 22cmx26cm baking dish with bread and cumquats, reserving six or seven fruit. Add custard as you go to allow it to soak into the bread. Finish with a layer of bread. Bake for 45 minutes or until golden and puffed up in the middle. Garnish with remaining cumquats and glaze with syrup.