Mix together the soy sauce, fish sauce and oyster sauce in a bowl. Rub half of the sauce over the pork and place in a small, nonstick roasting tin. Place in a preheated oven, 180°C (350°F), Gas Mark 4, for about 20 minutes or until cooked through but still juicy. Leave to rest for 5–10 minutes.
Meanwhile, heat the oil in a smoking hot wok or large frying pan and pour in the beaten eggs, swirling to cover the hot surface. Scatter over the sliced spring onions and cook for 1–2 minutes or until the egg is set and beginning to colour. Remove and slice thinly.
Put the broccoli in a steamer basket and lower into a shallow saucepan of boiling water so that the spears are not quite touching the water. Cover and steam for 3–4 minutes or until just tender. Alternatively, use a bamboo or electric steamer.
Cook the noodles in a large saucepan of boiling water for 3–4 minutes, or according to the packet instructions, until tender. Drain and heap on to serving plates.
Toss the broccoli in the remaining sauce mixture, spoon on to the noodles and scatter with the sliced omelette. Slice the pork and arrange over the noodles. Drizzle with any cooking juices and serve immediately.