For the rösti, boil the potatoes in their jackets for exactly seven minutes. Cool a little, then peel and grate coarsely.
Add the spring onions, garlic and plenty of salt and freshly ground black pepper.
Mould into patty-shaped röstis and chill for 20 minutes.
Heat a little olive oil in a frying pan and fry the röstis over a medium heat for four minutes on each side until crisp and golden. Drain on kitchen towel.
Preheat the oven to 200C/400F/Gas 6.
For the seabass, season the fillets well with salt and freshly ground black pepper. Heat a little olive oil in a frying pan and fry the fillets for a couple of minutes, skin-side down, then flip over and place in the oven for two minutes.
For the salsa, fry the bacon until crisp, then simply combine in a bowl with all the other ingredients.
To serve, place a fillet of sea bass on top of a rösti on each of four warmed plates and spoon over some refreshing salsa.