Preheat the oven to 200C/180C Fan/Gas 6. Line a large baking tray (big enough for the fish) with silicone paper.
Whisk the egg whites in a large bowl until foamy, then add the lemon zest. Chop half of the basil leaves and add them to the egg whites, then mix in all of the salt until well combined.
Slice one of the zested lemons and fill the fish cavity with the lemon slices and half of the remaining basil.
Spread one-third of the egg-white mixture onto the silicone paper lining the baking tray. Place the fish on top. Cover the fish completely with the remaining egg-white mixture.
Bake the fish in the oven for 30 minutes, or until the egg-white crust is golden-brown and the fish is cooked through (to check that the fish is cooked, stick a knife through the egg-white crust into the centre of the fish, then touch the blade of the knife - it should be hot.
Remove the fish from the oven and set aside to rest for 15 minutes while you make the salad.
Heat the vegetable oil in a frying pan over a medium heat. Add the bacon lardons and fry for 3-4 minutes, or until golden-brown and crisp at the edges. Transfer the bacon to a serving bowl.
Add the cooked potatoes to the same pan and fry for a couple of minutes, until heated through and browned on the edges. Add them to the bowl with the bacon, then stir in the red onion and the remaining basil.
Drain the artichokes, collecting the oil in a bowl. Stir the artichokes into the salad, and drizzle over some of the oil, as desired, to dress the salad. Season well with plenty of freshly ground black pepper, then mix to combine.
To serve, carefully remove the salt crust from the sea bass using a sharp knife and a fork, brushing any excess salt away from the skin of the fish as you go. Peel away the skin and lift the meat from the bones, picking all the meat from the fish on one side before removing the spine and lifting out the rest of the meat. Remove any large bones as you go. Serve a spoonful of salad alongside each serving of fish.