Pre-heat over to 180C and lightly grease a 9 x 5 inch loaf tin. Place cubed bread in a large bowl.
In a small bowl, whisk together 100ml of milk and arrowroot powder until no lumps remain. Add the remaining milk, syrup, vanilla, cinnamon and nutmeg and whisk to mix thoroughly. Pour over the cubed bread and stir to coat every piece. Allow the mixture to sit for at least 15 minutes, for the liquid to soak into the bread. Depending on what kind if bread you use and how stale it is, add more milk and allow more soaking time until every piece of bread is saturated and there's a little bit of extra liquid in the bowl. The mixture should look mushy and wet.
Fold in the chocolate chips and bananas, mashing the bananas slightly. Pour the mixture into the loaf pan, patting down to make an even top.
Bake for 30 - 35 minutes, until the top is puffed, slightly browned and feels firm.
Remove from oven and allow to cool before slicing and serving.