Preheat oven to 180 degrees C. Grease and flour a 23x33cm cake tin. Sift together the flour, bicarb soda, cinnamon and salt. Set aside.
In a large bowl, cream together the margarine and brown sugar until light and fluffy. Beat in the eggs one at a time. Beat in the flour mixture, then stir in the tinned fruit salad and syrup, mixing just until combined. Stir in the walnuts and chocolate chips.
Pour batter into prepared tin. Bake in the preheated oven for 35 minutes, or until a skewer inserted into the centre of the cake comes out clean. Allow to cool.