Heat two tablespoons of oil in a large frying pan and fry the pork shoulder until golden-brown on all sides. Remove the pork from the pan and set aside.
Add the chorizo to the pan and fry until crisp around the edges, remove from the pan and set aside.
Reduce the heat to medium and fry the onion and fennel for five minutes, or until softened.
Return the pork and chorizo to the pan, then pour over the stock, add the lemon juice and zest, cover and cook slowly on a low heat for two hours, or until the pork is very tender.
Add the chickpeas and olives and cook for a further 15 minutes.
Stir in the parsley and serve with wilted spinach.