Preheat oven to fan forced 170°C (or 180 with no fan). Grease and line a 20cm x 10cm loaf tin, with baking paper hanging over the edges so you can lift it out easily.
Mix the spelt flour and baking soda in a large mixing bowl. Add the salt and cinnamon and mix well.
Whisk the olive oil and honey together in a separate bowl. Add the eggs and mix well. Mash the bananas into the mixture, then add in the milk and vanilla and stir to combine.
Fold the wet ingredients through the dry ingredients until just combined then gently fold in blueberries, being careful not to overmix.
Pour the mixture into the prepared loaf tin and bake in the oven for 45-50 minutes, until a skewer inserted to the middle comes out clean.
Allow to cool in the tin for 5 minutes before lifting out and cooling on a wire rack for a further 15 minutes before slicing.