Spread the grapes and blackberries over the bottom of a medium-large sized baking dish.
In a bowl, combine the remaining ingredients and use a fork to mash the banana, oil and sugar into the oats and almonds.
Spoon the crumble topping over the fruit in the baking dish.
Place in the oven and bake at 180 degrees for 30 minutes, until the crumble starts to turn golden.
Serve immediately with a generous spoonful of creamy yoghurt.