Preheat oven to 200c/180c Fan/Gas 5. Line 2 large baking trays.
In a large bowl, combine the oil, golden syrup and peanut butter until fully combined into a sticky mixture. Stir in both sugars. Fold in the flour, baking soda and cocoa powder until a cookie dough forms.
Fold in the chopped chocolate and peanuts. Create 8 small balls of the dough (a large tablespoon of mixture each) and place on the trays, spaced apart. Press down before baking for 12-15 minutes.
Remove and let cool on a wire rack!