Christmas cake is best made early in the year. This allows the maximum amount of time for the flavours to mature, as well as allowing the regular sousing with brandy, whisky, whiskey, or bourbon to deepen the flavours.
Cream the butter, sugar, and treacle with the lemon rind until light and fluffy. Whisk the eggs and liquid together and slowly beat into the creamed mixture, adding a little of the sifted flour if it looks like it’s curdling. Gently mix in the fruit, nuts, peel, spices, and flour until just incorporated.
Put mixture into a greased baking pan and bake at 325f/160c for 1.5 hours, then drop the oven temp to 300f / 150c and bake for another 2.5 to 3 hours until a skewer inserted in the middle of cake comes out clean.
Store the cake in a cool dry place, in a sealed container, until it is Christmas time. If you make this more than a month in advance… which you are doing, right??… souse down the top surface with 1tbsp to 2tbsp of brown liquor (brandy, whisky, whiskey, bourbon) once a month. This will help preserve the cake as well as adding depth and complexity to the flavour.
You might want to look at my substitutions article, as well as my comments on Christmas Pudding when it comes to tweaking the recipe to taste/allergies.