Cut off a 4cm piece of ginger and grate. In a large bowl, mix 2 tbsp soy sauce with the honey, orange juice and zest, grated ginger and Chinese spice. Roll the pork in the sauce, coating well. Cover with clingfilm and place in the fridge to marinate for 1 hour.
Preheat the oven to 200°C/gas mark 6. Heat a large frying pan over a medium-high heat and seal the pork on each side for 2 minutes, until brown. Transfer to a roasting tin and pour over the marinade. Roast the pork for 20 minutes, basting halfway through with the pan juices, until cooked through.
Meanwhile, cook the rice according to the instructions on the packet. Shred the remaining piece of ginger. Heat the sesame oil in a wok and add the remaining soy sauce, along with the shredded ginger, garlic and chilli. Add the pak choi stems for the last 3-4 minutes until just tender.
Slice the pork and serve with the rice and pak choi, drizzling over any pan juices as a sauce.