Rinse fish cavity & pat dry with paper towel. Score or slash the flesh with a knife on either side behind the head of the fish (this assists in more even cooking).
Line a large bamboo steamer with baking paper. Take a small knife & slash 3-4 small holes into the paper to allow the steam through.
Place fish into the steamer & wrap the tail in lightly greased foil as it may be sticking out of the steamer. Cut the shallots into slices at a slight diagonal & cut the ginger into thin strips. Place half of the combined shallots & ginger into the steamer & top with the fish then add the remaining ginger & shallots.
Place the steamer over a wok or frying pan of simmering water & cover with lid. Cook fish for approx 6 minutes. Lift lid & place bok choy along either side of the fish, cover & continue to cook for a further 10 minutes approx. Remove from heat & stand covered for 2 minutes. Discard foil from tail.
Combine sauce ingredients in a covered container and shake well. Plate fish & pour the sauce over the fish & bok choy.