Remove the zest from the oranges and using a sharp knife, shred very finely into strips. Blanch this in boiling water for approximately 30 seconds and drain.
Carefully squeeze the juice from the oranges and add the juice from both lemons. Try to retrieve as much juice as possible from both.
Toast the flaked almonds in a frying pan until they start to colour and then tip into a small bowl. Add the butter to the hot pan and, when melted, add the demerara sugar: Gently cook the two together until the sugar melts and begins to caramelise. Then, add the citrus juice and the zest.
Cook until the sauce begins to thicken slightly and add the almonds. Turn the heat down low and add the four peeled whole bananas. Allow them to poach gently on one side for about 3 - 4 minutes, then gently turn over repeat the process on the other side.
Add the orange brandy to the syrup before removing the bananas. Place each banana in a crescent dish and pour the orange and almond syrup over each.
Whisk the egg whites in a bowl with a pinch of the caster sugar: When they are stiff, beat in most of the remaining caster sugar until the whites are thick and silky, keep back a little sugar to sprinkle over the top.
Using a piping bag and a medium star nozzle tube, pipe the meringue neatly over the bananas and scatter with the remaining sugar:
Place the bananas in the bottom shelf of a hot grill until they are glazed and golden brown. Serve hot with a ball of vanilla ice cream on each or double cream if preferred.