Heat the oil in a large frying pan. Add in the chorizo and fry for 2 minutes until it starts to release its oils, then tip in the potatoes and add some seasoning.
Pour in 3 tbsp of the white wine, cover the pan with a lid and leave to cook for 10-15 minutes until the potatoes are tender. Move them around the pan halfway through this time to stop them sticking and add a splash of water if required.
Season the fish. Add the tomatoes to the potatoes, along with the majority of the parsley and stir. Lay the fish on top and add in 1 tbsp of wine, placing the lid on top.
Leave to cook for 5 minutes, or until the fish has turned white and flakes easily.
Scatter the whole dish with the rest of the parsley and drizzle with some extra olive oil. Serve from the pan with crusty bread.