Heat half the oil in a large wok or frying pan and pour in the eggs. Cook, stirring, until set (about 1 minute). Remove, cool and then slice into strips.
Meanwhile, make the sauce by whisking together the ketchup, fish sauce, soy sauce and sugar. Heat the remaining oil in the wok until very hot and add the stir-fry vegetables and garlic, then cook over a high heat for 2 minutes, stirring constantly.
Add the noodles and egg strips, then stir-fry for a further minute. Add the sauce to the noodles and cook for a minute. Serve in bowls garnished with the chopped peanuts, coriander, chopped chilli and lime wedges.