The next day, drain the fruit and discard the liquid. Preheat the oven to 180 C / Gas 4. Grease a 900g loaf tin and line with baking parchment.
In a mixing bowl, beat together the butter and sugar until light and fluffy. Add the eggs, beating well after each addition. Add the milk and vanilla extract and mix well. Sift in the flour and baking powder then add the mixed spice. Mix well until the wet and dry ingredients are blended. Finally, stir in the peel and soaked dried fruit. Transfer to the prepared loaf tin and smooth the top.
Bake in the preheated oven for 60 to 90 minutes until firm to the touch and a skewer inserted into the centre comes out clean. Remove from the oven and allow to cool in the tin before slicing and serving.