Heat half the oil in a large non-stick wok or frying pan over high heat. Cook lamb, in batches, for 1-2 minutes or until browned. Set aside on a plate.
Add remaining oil to wok. Heat over medium-high heat then add garlic and onion to wok and stir-fry for 2 mins. Add rice and vegetables and stir fry for a further 2-3 minutes. Add bok choy and cook for 1 minute. Stir in sweet and sour sauce and cook for 1 minute. Return lamb to wok, toss well to heat through. Season.
Serve lamb stir-fry with green onion and chilli.
When stir-frying the meat wait at least 30 seconds before tossing or stir-frying. This gives the meat a chance to brown, giving it good colour and flavour. The second side will take a little less time to cook.
Once you return meat to the wok, take care that it does not boil in the liquid or it will toughen. Stir-fry only to combine and warm through.