For the poached megrim sole, trim the skirt and any unsightly blood lines from the soles. Using a sharp knife cut through the bones along one side of the spine from head to tail (cutting the fish in half). Cut the spine out of the other side. Repeat with the remaining sole.
In a sauté pan or a large frying pan, add the dashi powder and the fish stock. Bring to the boil then reduce to a simmer. Season the sole fillets with salt and freshly ground black pepper. Place in the simmering stock and cook for 4-6 minutes. When cooked, drain the fillets (reserving a tablespoon of the cooking liquor) and set aside until ready to serve.
To make the butter sauce, place a frying pan over a medium heat. Add a knob of butter and the shallot, bay leaf and peppercorns. Cook for 2-3 minutes, then add the white wine, white wine vinegar and a tablespoon of the cooking liquor from the fish. Simmer until the liquid has reduced by three-quarters.
Stir in the double cream, then slowly incorporate the remaining butter. The sauce should be thick enough to coat the fish fillets. Season to taste with salt and freshly ground black pepper.
For the warm quinoa and sea herb salad, in a pan bring the stock and dashi powder to the boil. Add the quinoa and cook until the grains are tender and the stock has evaporated. Remove and place in a bowl.
In a pan of boiling water, briefly cook the samphire and sea beet. Transfer to a bowl of iced water to refresh.
In a dry frying pan, lightly toast the fennel and onion seeds then add to the quinoa along with the fennel pollen. Add the tomato, lemon, cucumber, red onion, parsley, wild garlic leaves and the cooked samphire and sea beet. Mix together and season to taste with salt and freshly ground black pepper.
Just before serving, add the nori seaweed to the sauce.
To serve, place the sole fillets on serving plates next along with a pile of the quinoa salad, garnish with the flowers. Pour the sauce over the fish and serve immediately.