Place a stewing pot over a medium heat. Drizzle in a tablespoon of olive oil, then add the garlic, prawns and scallops. Lightly sear on both sides, then set aside.
In the same pot, add the daikon and pan-fry for a few minutes. Then add OFJ dashi powder, canned tomatoes, tomato paste and water. Simmer till the daikon is soft.
Add the prawns and scallops, then bring to the boil.
Season to taste with salt and pepper.
Garnish with dill and bonito flakes, then serve.