Brown well seasoned shanks in a spot of oil and remove from pan.
Diced celery, onion, and carrot in pan and sautee for a few. Add SP, garlic and fresh thyme for the last minute then hit with some wine. Bay leaf wouldnt hurt.
Dump veg mix in slow cooker with some stock and a bit of tomatoes paste or whatever tom product you like.
Set meat on top and cook on low until tender. Meat should be in liquid, not under.
I'd take some of the pot likker when its done and reduce it in a sauce pan to make a sauce.