For the soused mackerel, fillet the mackerel and cut down each fillet lengthways to remove the centre bone line.
Cut the mackerel fillets in half, to create four mini fillets from each side. Season the fillets with salt and leave for 10 minutes to lightly cure.
For the pickling marinade bring 200ml/7fl oz water, the vinegar and white wine to the boil with the peppercorns, star anise and coriander seeds, add the orange zest, juice, saffron and sugar. Simmer for a couple of minutes.
In a deep tray or dish add the finally sliced fennel, top with the mackerel fillets skin side up, lay over the finely shaved carrot ribbons and shallots over the mackerel along with the coriander.
Pour the hot pickling marinade over the mackerel, making sure to cover the fish. Cling film the top of the dish to trap in the hot steam, and leave to cool. This will allow the fish to cook and lightly pickle at the same time.
Place the mackerel in the fridge for at least 30 minutes, but it can be kept for up to two days.
For the pickled orange zest, blanch the orange zest in boiling water for about a minute, then drain and refresh in iced water.
In a separate pan bring 125ml/4fl oz water, the sugar and vinegar to the boil and simmer for about three minutes.
Add the orange zest to the syrup and cook for a further five minutes. Remove from the heat and set aside to cool before using.
For the smoked eel, heat a deep fat fryer to 180C/350F, or alternatively heat vegetable oil in a deep-sided, heavy based pan, until a breadcrumb sizzles and turns brown when dropped into it. (CAUTION: hot oil is dangerous. Do not leave unattended.)
Cut the smoked eel into 2cm/1in cubes. Place the flour, egg and breadcrumbs in separate bowls. Season the flour with salt and freshly ground black pepper. Toss the smoked eel first in the seasoned flour, then dip into whisked egg and finish in the breadcrumbs.
Carefully place the breadcrumbed eel into the hot oil and cook for 2-3 minutes until golden-brown. Remove the eel from the hot oil with a slotted spoon and drain onto kitchen paper then season with salt.
To serve, remove the mackerel from the fridge and llow to come to room temperature. Spoon a little fennel into the centre of each serving bowl and top with the soused mackerel fillets. Garnish with the carrot ribbons, pickled orange zest, arrange the breaded smoked eel next to the mackerel and finish with a little of each of the cresses.