I bought a piece about the size of half a rugby ball for pocket money in the market. The butcher told me to do this if I had a slow cooker - course I do.
Seal the joint in a lightly oiled pan then transfer it and the juices to the SC. Add two onions, cut in quarters lengthwise, and then a couple of cans of beer/lager - enough to come half way up the joint. Drink any leftovers. Season with a beef stock cube and pepper to taste.
Cook on high for the first hour, then on low overnight. Before serving drain off the gravy and thicken with a butter/flour roué - he said "paste", but I knew what he meant.