Heat a large pan with a lid. When hot, tip in the mussels. Add the wine, place the lid on and cook until the mussels open (about 5 mins). Don’t overcook and discard any that don’t open. Drain in a colander, saving the liquid and the mussels separately.
Heat half the oil in a paella pan or large deep frying pan. Add the chicken thighs and chorizo and brown, turning. Stir in the garlic, onion, pepper and cook till softened. Stir in the rice.
Add the chilli flakes and reserved mussel cooking liquid, chicken stock and soaked saffron and liquid. Stir well, bring to boil and simmer gently for 10 mins.
Stir in the tomatoes, peas and prawns and cook gently for 10 more mins.
Once nearly all the liquid is absorbed and the rice tender, scatter mussels on top to heat through for 2 mins. Scatter over chopped parsley and serve with lemon wedges.