Score the chicken thighs with a sharp knife and place them in a large bowl. Add the paprika, sweet paprika, cayenne pepper, a pinch of salt, and a good grind of black pepper. Massage the spices into all the chicken. Set them aside.
Dice the chorizo into rounds, set them aside. Heat the Dutch oven over medium heat. Add the chorizo and fry until slightly crispy and the fat begins to melt. Remove the chorizo using a slotted spoon and set it aside.
Dice the celery and peppers into small cubes. Add the celery to the Dutch oven and cook for 5 minutes until it starts to soften. Add the chopped peppers and cook for a further 2 minutes.
Remove the stalk ends from the okra. Dice into ¼-inch rounds. In the same Dutch oven, add the okra and continue to cook for 5 minutes until they begin to soften.
Pour in the canned chopped tomatoes and the hot chicken stock. Add the bay leaves and thyme sprigs. Stir through. In a small bowl, add the arrowroot flour with 2 tablespoons of cold water. Stir to dissolve then add to the mixture and stir with a wooden spoon until it thickens slightly. Carefully place the chicken thighs into the Dutch oven allowing space between them and toss in the chorizo pieces. Ensure all the chicken, chorizo and okra are submerged in the sauce.
Cover the Dutch oven with the lid and leave to simmer for 30 minutes. Remove the lid and continue to simmer for a final 10-15 minutes to allow the gumbo sauce to reduce and thicken. Remove and discard the bay leaves and thyme sprigs.
Taste the gumbo and check for seasoning. Season again if necessary. Ladle into shallow bowls and serve with freshly chopped parsley and alongside boiled rice, potato, or gluten-free bread (optional).