In a large bowl add the raisins, currants, dried cranberries, walnuts, orange juice, orange zest, lemon zest, mixed spice, ground cinnamon, chia seeds and sugar. Mix well. Cover and leave to soak for around 2 hours (or overnight).
Preheat the oven to 180°C/ 160°C fan/ Gas 4. Line a baking tray with greaseproof paper.
Uncover the mincemeat mixture and add the chopped apple and walnuts and combine well.
Remove the filo (room temp) from the packaging. Take 2 sheets (cover the other sheets with a damp tea towel when not using). On one sheet brush the edges and middle lightly with the melted butter. Place the second sheet directly on top and press down so they stick together (the butter acts as glue).
Using a pizza slicer or knife cut the sheet into quarters (4 squares). Place around 2 tablespoons of the mixture in the middle of each square. Brush the edges with the melted butter. One square at a time, take each corner carefully and gather into the middle, pinch together at the top to enclose the filling. Place onto the baking tray.
Repeat step 5 until you have used all the mixture.
Lightly brush the parcels, including tops, with the remaining melted butter.
Place into the oven, on the middle shelf for 25-30 minutes until the tops and edge are golden.
Once cooked, remove from the coven and transfer carefully to a wire rack to cool slightly before dusting with icing sugar.
Enjoy these warm or at room temperature.