Toss the candied orange peel, walnuts, raisins and sultanas with 2 tablespoons flour. Set aside.
In a large bowl, cream the butter with the sugar and honey. Beat in the egg, then the cream or milk, rum and vanilla. Stir together the remaining flour and the baking powder; beat into the creamed mixture. Stir in the fruits and nuts. Turn the cake mixture into a greased and floured 1 lb loaf tin.
Bake in a preheated 180 C / Gas 4 oven for 10 minutes. Lower the heat to 170 C / Gas 3. Bake the cake 45 minutes longer, or until it tests done with a skewer. Transfer to a rack to cool.