Preheat your oven to 165°C (325°F) / 145°C fan / gas mark 3.
Grease a 26 x 12cm (10 x 5 inch) loaf tin with butter or oil, then line the base and sides with baking parchment.
Spread the oats and desiccated coconut on one non-stick baking tray, and all the chopped nuts on another. Toast in the preheated oven for 10–20 minutes, or until fragrant and golden brown.
Toss with a spatula every 5 minutes to ensure they toast evenly without burning.
While the nuts are toasting, pour 150ml (5.1 fl oz) of water into a small saucepan.
Add the chopped dates and bicarbonate of soda.
Set over a medium heat for about 5 minutes, until the water has mostly evaporated and the dates are very soft. (Don't be alarmed if the bicarb turns the dates a dark green colour – this is normal!) Use a hand-held blender to blitz the mixture into a smooth purée.
In a large mixing bowl, combine the warm date purée with all the remaining , including the toasted oats, coconut, and nuts.
Stir everything together until thoroughly mixed.
Spoon the mixture into your prepared loaf tin, pressing it down firmly and evenly.
Bake for 30–40 minutes, or until the top is golden and the bar is firm to the touch.
Let the bar cool in the tin for 10 minutes before carefully turning it out onto a wire rack to cool completely.
Once cool, use a sharp knife to cut it into 8 thick slices.