Place the diced figs in a bowl. Add lemon zest, lemon juice and rum, cover and set aside to soak overnight.
Grease a 1 1/2 litre pudding basin and place a small disc of greaseproof paper on the bottom.
Beat together the butter and sugar until light and fluffy, then gradually beat in the eggs. Add the apple, pear, almonds, glace cherries, ginger and soaked figs; mix well. Sift in the flour and add the breadcrumbs.
Spoon the mixture into the pudding basin and smooth the top. Lay a doubled sheet of greaseproof paper and then a doubled sheet of foil on top and fold together to make a pleat in the centre (this allows for expansion). Smooth the paper and foil down around the basin and tie securely with string under the edge.
Steam for 3 hours, topping up with more boiling water when necessary. Remove the basin from the steamer and take off the foil and paper lid. Cover loosely with a tea towel and let cool.
When the pudding is cold, cover with doubled sheets of fresh greaseproof paper and foil and keep in a cool dark place up to 3 months.
On the day of serving, steam a further 1 1/2 hours. Turn out on a serving plate and serve with the rum sauce in a small jug.
To make the sauce, blend the cornflour with 6 tablespoons cold milk. Heat the remaining milk until almost boiling then pour onto the cornflour mixture, stirring. Return to the saucepan and stir over moderate heat until thickened. Simmer a further 1-2 minutes, all the while stirring. Add the sugar, ginger syrup and rum, then test for sweetness.