Preheat the oven to 180 degrees C. Grease three 23cm round cake tins and set aside.
In a large bowl beat butter and sugar until light and fluffy. Add eggs one at a time, mixing until each one is blended in. Dissolve the bicarb soda in the water; stir into the batter along with the blackberry jam.
Combine the flour, cloves, nutmeg, cinnamon and salt; stir into the batter by hand, alternating with the buttermilk. Fold in the walnuts and sultanas. Divide the batter equally between the three tins and spread in an even layer.
Bake in the preheated oven until the top of the cakes spring back when lightly touched, about 35 minutes. Cool in the pans until cool enough to handle then invert the cakes over a wire rack and remove pans to cool completely.