Combine the apples in a saucepan with the sugar, lemon, water and butter and bring to a simmer. Cover and cook until tender.
Add the dates and walnuts, stir, and place in a small baking dish.
Mix the flour with the coconut and sugar. Melt the butter and pour over the flour mixture. Stir well. Scatter the crumble evenly over the top of the fruit.
Bake about 25 minutes or until the topping is just getting crisp. Serve hot with ice cream.