Soak beef bones for 24 hours, changing water four times, then extract and slice marrow.
Dredge beef shin in seasoned flour.
Brown the beef shin in beef dripping in a large saucepan for 5 minutes and set aside.
Fry onions for 10 minutes, add red wine to reduce by half, then add stock and bouquet garni.
Simmer the filling covered for one hour, then uncovered for 15 minutes until tender.
Cool the filling mixture in a large bowl.
Reduce chicken stock, beef stock, and tomato juice by three-quarters over 2 hours for the sauce.
Simmer shallots and red wine in a separate pan until the liquid evaporates.
Strain reduced sauce stock into the shallot mixture and season.
Grease a 1.75 litre pudding basin with butter.
Combine self-raising flour, suet, water, and salt into a dough.
Roll three-quarters of the dough into a 25cm circle and line the basin.
Roll the remaining dough into a lid 1cm thick.
Add the filling to the basin, top with the lid, and seal the edges with water.
Wrap basin in foil, secure with string, and steam in a water bath for 1.5 hours.
Boil potatoes for 15 minutes, drain, and mash with butter and cream.
Melt bone marrow into the sauce just before serving.
Unmould the pudding, slice, and serve with sauce and mashed potatoes.