Heat the olive oil in a large heavy-bottomed saucepan. Season the lamb with salt and pepper then cook in the hot oil until browned; 2 to 3 minutes. Add the garlic and cook stirring for 1 minute.
Pour the red wine and chicken stock into the saucepan and bring to a boil while scraping the browned bits of food off of the bottom of the pot with a wooden spoon (deglazing). Reduce the heat to medium-low then add the tomatoes, oregano and bay leaf to the saucepan. Simmer gently until the lamb is tender; about 45 minutes.
Raise heat to medium-high. Add the potatoes, green beans, red capsicum and zucchini to the pot. Cook until the vegetables are tender; another 15 to 20 minutes. Sprinkle the parsley over the casserole. Remove the bay leaf and season with salt and pepper before serving.