Tie each piece of veal shank around its girth to secure the flesh. Dust with flour, salt and pepper. Heat the oil, butter and garlic in a large heavy saucepan big enough to hold the shanks in a single layer. Put shanks in the pan and cook for 12-15 minutes until well browned. Arrange the shanks, standing them up in a single layer, pour in the wine and add the bay leaf, allspice, and cinnamon. Cover the saucepan.
Cook at a low simmer for 15 minutes, then add 125 ml warm water. Continue cooking, covered, for about 45 minutes to 1 hour (timing will depend on age of veal) until meat is tender and you can cut it with a fork.
Check the volume of the liquid once or twice and add more warm water as needed. Transfer the veal to a plate and keep warm. Discard the garlic clove and bay leaf.
To make the gremolata, mix together the lemon zest, parsley and garlic. Increase the heat under the saucepan and stir for 1-2 minutes until the sauce is thick, scraping up any bits off the bottom of the saucepan as you stir. Stir in the gremolata. Season with salt and pepper, if necessary, and return the veal to the sauce. Heat through, then serve with the lemon wedge.