Mix 1 cup stock, tomato paste and flour in slow cooker until lump-free (use whisk if needed) then mix in remaining stock.
Sprinkle beef with salt and pepper, heat oil in large fry pan (skillet) on high heat. Brown beef pieces in batches (~3 – 4 min), add to slow cooker (leave fat in pan).
Saute onion in remaining fat until tinged gold and softened. Add wine and boil until reduced by 75%. Add to slow cooker.
Add stock cube, Worcestershire, bay leaves, thyme, salt, pepper, stir. Add carrots, celery and potato, push in to submerge as best you can (some sticking up is fine).
Slow cook 10 hours on low or 6 hours on high. Stir in peas, leave for few minutes, serve stew over mash or with crusty bread for dunking!
