Gravy ingredients are available from Fiesta.
Cook onions in oil until transparent. Brown ground beef and drain off excess fat. Add water, crumble bouillon cubes, marmite and carrots. Simmer gently for 10-20 minutes, stirring frequently, do not let it cook dry. Add more water if necessary. Mix bisto according to directions on tin and add to meat mixture, stirring continuously until the gravy thickens. Place meat mixture into an oven proof casserole dish, if the gravy covers the meat mixture drain off and reserve to use later. I would advise to make lots of gravy. Spoon peas over mixture, and top with mashed potatoes, making a design with a fork on top. Place under broiler until top is a golden brown and serve immediately with the extra gravy.