Soak the dates in half a cup of water for an hour. Grind it into a thick purée and set aside. Break the almonds and cashews into 2s and 3s and dry roast all the nuts and seeds and set aside. Dry roast the oats and grind to a powder. In a large pot heat the dates purée, add honey, lemon and salt. Once it has thickened, add the nuts, cranberries and oats and mix well. Pour on to a tray lined with baking paper and pat down with a spatula. Refrigerate for an hour and cut into squares/bars. This is not very sweet. If you want, you can add raisins as one of the ingredients to increase the sweetness.