Preheat oven to 300F and line 2 loaf pans with parchment paper. Set aside.
For the tea, place 400ml boiling water in a measuring cup. Place tea bags in measuring cup and allow tea to steep for 5 minutes. Meanwhile place raisins and prunes in a very large bowl.
When tea is ready, discard tea bags and pour tea over top of fruit. Add butter so it can melt in the hot tea. Allow mixture to sit for a few minutes so the fruit can soak up some of the tea.
Add treacle, sugar and malt extract to the bowl and mix to combine. Beat in the eggs and then add in both flours, baking powder and baking soda. Fold to combine. Divide between the two loaf pans and bake for 1 hour or until loafs are risen and spring back to the touch.
Cool in tins on a wired rack for 10 minutes. Remove loafs from the pan and cool completely. Wrap loaves in parchment paper and store in a cool, dry area for at least 24 hours. Loaves will keep for 1 week.