Preheat the oven to 160 C/140 C fan/gas 3.

Grease a 20x7cm loaf cake tin, then place a long piece of parchment paper to cover the bottom and the two shorter sides, leaving the longer sides unlined. Make sure the parchment paper is long enough to fold slightly over the top of the tin, so you can use these ends to lift out the loaf once baked.

In a large mixing bowl, combine the dry ingredients- plain and wholemeal flours, sugar, baking soda and powder, spices, and salt. Mix together well, then make a well in the middle for the wet ingredients.

Into the bowl, add the oil, flax egg, non-dairy milk, vanilla, and orange zest. Stir together until completely incorporated, then fold in the apples and walnuts.

Transfer the mixture into the loaf tin and bake on the middle rack of the oven for about 1 hour 20 minutes, or until a toothpick comes out clean.

Remove the loaf from the oven and cool for 15-20 minutes before removing from the tin. To do this, run a knife or small spatula carefully around the edges of the tin to loosen the loaf. Allow the loaf to cool completely on a cooling rack.

Once ready to serve the loaf, prepare the glaze by whisking together the powdered sugar, orange juice, and mixed spice until smooth and creamy. Drizzle over the loaf and allow it to set for a few minutes before slicing the loaf and serving.