Preheat the oven to 150°C.
In a large heavy metal casserole dish (with a lid), fry the bacon, celery and onions in a little oil until translucent. Remove and reserve.
Dust the meat with flour. Pop the pieces in a sieve and give them a jiggle to remove any excess flour. Fry the beef quickly in oil, and in 3 batches, in the same pot until browned on all sides. Remove and reserve each batch until the final batch is browned.
Mash up the anchovies in the base of the pot and then deglaze the pan with the stock. Throw in the carrots, bay leaf, prunes, beef, bacon, celery, onions and stout. Put the lid on the pan and place in the oven for 3 hours.⏱ 180 min
At the end of cooking, check the braise and add salt and pepper if required. The prunes and the saltiness of the anchovies should temper any excessive bitterness from the stout but a little extra salt at the end can help highlight the stew's flavour and counter bitterness.