Preheat oven to 180°C fan forced. Grease and line the base and sides of an 18cm x 28cm (base) slice pan.
Combine flour, sugar and coconut in a bowl. Add butter and mix until combined. Press over the base of prepared pan. Bake for 15 minutes, or until light golden.
Combine all the filling ingredients in a medium saucepan. Stir over a low heat until sugar has dissolved. Bring to a boil and simmer, stirring gently, for 2-3 minutes, or until thickened. Remove. Spread over warm base.
Combine all the topping ingredients in a bowl. Sprinkle evenly over the blueberry filling. Return to the oven and bake for 22-25 minutes, or until crumble is golden. Set aside to cool for 1 hour then refrigerate. Cut into slices to serve.