1) Preheat the oven to 200C/Gas 6. Arrange the peaches in the bottom of a shallow baking dish. Set aside.
2) In a small bowl, combine the flour, oats, oil, brown sugar and cinnamon. Stir with a fork until the mixture is crumbly, adding more oil if necessary.
3) Fold in the nuts. Sprinkle the topping over the peaches and bake for 15 minutes, until the crumble is golden brown.