Much as I like French food, I still hanker after an English Christmas cake. However, I cannot easily find the ingredients. H.S.
The ingredients can either be sourced, with a little searching, or replaced with substitutes. For example, you will not find “mixed spice”, as this is a traditional British spice mixture (it should not be confused with allspice, piment de la Jamaïque in French). However, you can make it with its ingredients, which include about an equal quantity each of ground allspice, cinnamon (cannelle), cloves (clous de girofle), nutmeg (noix de muscade) and ginger (gingembre).
You can use mélasse (molasses) in place of dark treacle, while golden syrup is called mélasse raffinée and can be found in health food shops (or British sections of big supermarkets and British food stores). Maple syrup or runny honey are alternatives.
A French marzipan called massepain exists, but the more common equivalent is pâte d’almondes (almond paste). You can also make your own from ground almonds, confectioner's sugar (sucre glace), egg whites and vanilla extract.
Candied peel is écorce d’orange et de citron confit and is often found in baking sections in supermarkets. As for other dried fruits: sultanas are called raisins golden, raisins are raisins secs, and raisins de Corinthe are currants