Preheat the oven to full whack. Put the rock salt into a large, wide bowl with 2 tablespoons of water, your eggs, fennel seeds and the peeled rind of the lemon. Mix everything together until sticky and claggy, then spread two-thirds of the mixture around the base of a roasting tray in a thick layer. Stuff the cavity of your fish with the basil and parsley (or any fragrant herbs), then lay the fish on the salt bed, and completely cover it with the rest of the salt so you get a layer just over 1.5cm thick. Pat it down firmly, then put into the oven for 15 minutes.
Once cooked, remove from the oven, take a sharp knife and stick it through the salt into the middle of your fish. Carefully touch the knife to your lip and if it’s hot, the fish is ready. Leave to one side for 10 minutes.
Meanwhile, pound and mush up the garlic, saffron and a good pinch of salt in a mortar and pestle until you’ve got a smooth vibrant orange paste. Use the pestle to mix in the olive oil, a drizzle at a time. Be patient and wait until you’ve got a smooth emulsion before adding the next drizzle. Do the same with the extra virgin olive oil. If it splits, pour the mixture out, pound some more garlic and salt together, then really slowly add the split mixture to that. Be patient! Have a taste. Initially it will be fiery and you’ll think you don’t like it, but it’s supposed to be that way. Add a squeeze or two of juice from your peeled lemon and taste again.
Roughly slice your cucumber and put it into a bowl. Tear the olives and add to the bowl along with the torn-up peppers, the parsley, a squeeze of lemon juice and a drizzle of extra virgin olive oil. Season with a little salt and pepper, then toss together.
By now the salt on your fish should be hard as a brick, so give it a whack around the edges with the back of a spoon, and if you're lucky, the whole top will peel off. Carefully brush the excess salt off your fish, trying not to let the salt touch the flesh, then gently move it to a platter using a fish slice. Run a knife along the spine of the fish up to the head, then cut across the fish below the head. Use the knife to find the bones, then carefully lift the fillet up so the fish opens like a book. Discard the skin and bones and put beautiful big flakes of fish on your serving plates with a dollop of your aioli on top and some olive salad.