Break up the digestive biscuits with a food processor (or put them in a plastic bag and crush them with a rolling pin). Leave some small chunks to give the tiffin texture.
Melt the non-dairy spread in a pan or the microwave.
In a large bowl, mix all of the ingredients except the chocolate together, adding the cranberries last. Save a few to sprinkle on the top.
Line a lightly greased baking tray with greaseproof paper and press the mixture down firmly to a depth of about 1cm. If the tray is too big, only half fill it.
Melt the chocolate in a bowl over a pan of hot water (or on a low setting in the microwave). Pour over the surface of the tiffin mix and spread it evenly, all the way to the edges. Sprinkle the rest of the dried cranberries on top.
Chill in the fridge for at least two hours. Cut into small rectangles using a knife dipped in hot water to prevent the chocolate from cracking.
Recipe by Veggie Runners at https://www.veggierunners.com/2016/01/12/vegan-cranberry-tiffin/