Put the mixed fruit in a large bowl and cover with boiling water. Set aside to soak for 10 to 15 minutes, then drain well.
Put the margarine and sugar into a pan and heat gently until it is melted. Then add the dried fruit and cook over a low heat for 5 minutes. Remove from the heat and transfer into a mixing bowl. Set aside to cool.
Sift the flour and salt into the mixture and stir well. Add the eggs and mix them until they are thoroughly blended together.
Add the pineapple and cherries to the cake mixture and stir well. Transfer to a greased and lined loaf or cake tin and level the surface.
Bake the cake in the preheated oven until a fine skewer inserted near the centre comes out clean, about 1 hour. Remove from the oven and leave to cool before serving.
You can substitute the margarine for butter if you like.