It will depend on which type of Plum Pudding he made. I've seen some recipes that use carrots and Guiness, and others that use neither. There are differences in the recipe between and English Plum Pudding, Irish Plum Pudding and the American version. I can only vouch for the English version which is gorgeous!
And of course, despite it's name, it doesn't contain plums. It is pretty much a 'heavy' fruitcake - very dark and moist, and of course the fruit is ideally soaked in brandy.