Heat the oil in a paella pan or wide, heavy-bottomed frying pan.
Brown the chicken thighs, pork cubes, squid, and chorizo, then remove and set aside.
Fry the chopped onion and garlic in the same pan for 3-4 minutes until softened.
Add rice, rosemary, saffron with its milk, and 500ml of stock.
Simmer for 18-20 minutes, adding stock if the rice becomes dry.
Return chicken and pork to the pan and simmer for 10 minutes until chicken is cooked.
Add the cooked squid, chorizo, prawns, assorted fish, and tomatoes.
Cook for 8-10 minutes until the fish and prawns are cooked through.
Serve in warmed bowls with lemon wedges.