Sausage & Haricot Bean stew

225g dried haricot, cannellini or flageolet beans (or 2 x 400g tins of cooked beans)

bouquet garni

1 carrot, peeled

1 onion, peeled

3 tbsp extra virgin olive oil, plus extra for frying

450g fennel and chilli pork sausages or best pork sausages

175g chopped onion

4 large garlic cloves, crushed

1 x 400g tin of plum tomatoes, chopped

1 tbsp chopped rosemary

flaky sea salt, freshly ground black pepper and sugar

flat-leaf parsley or chervil, to serve