Very sorry for not getting back to you about this, things happened and I have not been able to access the CB for a few days. Unfortunately, the crumble does have hazelnuts, but you could try leaving them out and use flour instead, as they're part of the crumble topping? Also, the recipe is in weights instead of volume measurements, but if you have a kitchen scale then you can use that. Without further ado: 

Ingredients (for the filling):
Butter (for greasing)
450g/1 pound cooking apples
115g/4oz blackberries
grated rind and juice of one orange
50g/2oz light brown sugar

Ingredients (for the topping):
175g/6oz flour (all-purpose I think)
75g/3oz butter
75g/3oz white sugar
25g/1oz chopped hazelnuts (substitute with something else; they are ground up to add to the topping so you could use flour?)
2.5ml/1/2 tsp crushed cardamom

Method:
Butter a 2 pint (1.2 liter) baking dish generously. Peel, core, and slice the apples and place them in the dish. Scatter blackberries over them and sprinkle with orange rind and brown sugar. Mix flour and butter in another bowl until they resemble coarse breadcrumbs, then add white sugar, hazelnuts (in this case something else) and cardamom. Spread the topping mixture over the fruit and press down on it until it forms a sort of crust. Bake it in a preheated oven at 200 degrees C/400 degrees F for 30-35 minutes until golden. Serve hot, with custard, ice cream, or something similar.