Coat the chops with the flour seasoned with the pepper and salt.
Brown on both sides in the oil and remove the chops.
Cook the chopped onions in the oil until soft and golden and put into the crockpot.
Work any remaining flour into the fat, cook for 2 minutes, and stir in the stock.
Bring to the boil, stirring well.
Put the thinly sliced carrots, celery and apple into the crockpot.
Put the chops on top and pour over the thickened stock, seasoning to taste.
Cover and cook on HIGH for 30 minutes, then on LOW 6-7 hours.