Preheat the oven to 170°C fan forced. Grease and line the base and sides of 6cm deep, 10cmx21cm (base) loaf pan.
Place the dates into a heatproof bowl, add 2 tablespoons of boiling water. Cover and stand for 10 minutes. Coarsely chop 2/3 cup (75g) walnuts. Set the remaining 1/3 cup aside for the top.
Sift the spelt flours, baking powder, bicarbonate of soda and cinnamon into a large bowl, adding any husks left in the sieve from the wholemeal flour. Stir in the chopped walnuts.
Coarsely mash the bananas on a plate with a fork (you should have 11/3 cups). Transfer to a jug. Add the oil, eggs, date syrup and softened dates including any water. Stir to combine. Add to the flour mixture and stir gently until just combined.
Spoon the mixture into the prepared pan and smooth the surface. Top with the reserved walnuts. Bake for 45-55 minutes or until a skewer inserted in the centre of the loaf comes out clean. Remove from oven. Stand 10 minutes in the pan then lift onto a wire rack.
Slice and serve warm or serve toasted in a sandwich press spread with peanut butter.