Pre-heat the oven to 200°C.
On a low heat, melt together the butter, brown sugar and golden syrup.
Remove from the heat and add the oats.
Add the raisins and chocolate chips and stir until fully combined.
Add mixture to large baking tray.
Bake for 25 minutes or until golden brown.
Remove the flapjack from the oven and place on a wire rack.
Use a knife to pre-score the flapjack so it is easier to cut once cooled.
Leave the flapjack to cool overnight before cutting and serving.