1. Preheat the oven to 350 degrees Fahrenheit (175 degrees Celsius).
2. In a saucepan over a low heat, combine the butter, brown sugar, and golden syrup. Cook, stirring occasionally until the butter and sugar have melted. Stir in the oats and raisins until coated.
3. Pour the mixture into a 7 or 8-inch baking pan – the mixture should be about 1-inch thick
4. Bake for 30 minutes, or until the top is nice and golden. Cut into squares, then let them cool completely before removing from the pan.