Start by making your teriyaki marinade. Pour the tamari into a bowl and add 1 tbsp Demerara sugar. Peel and grate in the ginger and 1 garlic clove. Stir together and pour into a large dish.
Lay the haddock fillets in the dish and turn to coat in the marinade. Set aside for 10 mins.
While the haddock marinates, trim the roots and top 3cm off the spring onions. Finely slice the spring onions. Rinse the radishes and shake dry, then slice off the leaves (keep the leaves for later). Slice each radish into quarters. Peel the carrots and slice into matchsticks. Thinly slice the coriander stalks (save the leaves for later). Halve the chilli, flicking out the seeds and pith for less heat, and finely chop the chilli. Peel and grate the remaining garlic clove.
Fill up a pan with boiling water and return to the boil. Add a pinch of salt, drop in the noodles and cook for 3-4 mins till tender, then drain and rinse thoroughly with cold water till cool. Drain again and set aside.
Set your grill to a high heat. Set a large frying pan or wok over a high heat and warm for 2 mins.
Lift the haddock out of the marinade and place on a baking tray, skin-side up. Slide under the grill for 4-5 mins, till the skin is crisp and the flesh flakes away when pressed with a fork.
While the haddock is cooking, pour 2 tbsp oil into the wok and stir in the carrots, radish quarters, coriander stalks, chilli, garlic and spring onions. Stir fry for 2 mins. Stir in the cooked noodles, radish leaves and any leftover marinade. Stir fry for a further 2 mins till warmed through.
Pile the noodles and veg onto a couple of plates and top with the grilled haddock. Finish with a scattering of coriander leaves and wedges of lime.