Preheat the oven to 170 C / Gas 3. Line a 900g loaf tin.
Mix the flours, baking powder and cinnamon together. Rub in the butter or margarine until it resembles fine breadcrumbs.
Combine the bananas, honey, golden caster sugar, lemon zest and eggs together and then mix that into the flour mixture. Keep beating together until fully incorporated. Now add in the walnuts. Tip into the loaf tin.
Bake on the middle shelf for approximately 1 hour. Allow to cool for 10 minutes in the tin before turning out onto a wire rack.
Use for leftovers
Can be used for French toast for a decadent Sunday brunch. Just soak in an egg and milk mixture as for normal French toast and serve with bacon and maple syrup. Yummy.