Start this recipe by lining the base and long sides of a 900g/2lb loaf tin with greaseproof paper, buttering the tin and paper. Tip the flour, cinnamon, butter, sugar, honey and the eggs into a large mixing bowl and beat the mixture for 2-3 minutes, using a wooden spoon or hand-held mixer, until well blended. Stir in the mashed bananas and chopped dates. Spoon the cake mixture into the prepared tin and level the top with a palette knife. Scatter the walnut pieces over the top and bake in the oven at 140`c for 1 hour. Check by lightly pressing the top, it should feel firm if cooked. If not, bake for a further 10 minutes. Remove the cake from the oven and leave to cool for 15 minutes, and then lift it out of the tin using the paper. When cold, serve the date and walnut cake cut into thick slices.