For the cured salmon, place the beetroot, fennel seeds, tarragon, salt and sugar in a food processor and blend together to make a purée for the cure.
Lay the salmon skin side down on a large tray and spread the cure over it, ensuring the salmon is evenly covered. Cover with cling film and then place in the fridge for about 10 hours.
Turn the salmon over, cover with cling film again and continue to cure for another 20 hours.
Wash off the cure and pat the salmon dry with kitchen paper - at this stage the salmon is ready to eat. Wrap the fish in cling film and keep in the fridge until ready to serve.
For the smoked mackerel pâté, place all the ingredients in a food processor and pulse until smooth. Chill the pâté until ready to serve.
For the beetroot salad, wash the beetroot and place in a pan. Add enough water to cover the beetroot then add a pinch of sea salt and a dash of the vinegar.
Bring the water to the simmer and cook until the beetroot is soft but not breaking up - time will vary depending on the size of the beetroot, but it could take up to an hour. Allow the beetroot to cool in the water and then peel and dice into 5mm/¼in cubes.
Place the beetroot into a bowl and then add the shallot, garlic, a pinch of salt, freshly ground black pepper and the remaining vinegar. Cover with the olive oil and set aside until ready to serve.
For the oysters, place the flour, egg and breadcrumbs into three separate bowls. Season the flour with salt and freshly ground black pepper.
Dip each oyster into the flour, then the egg and finally the breadcrumbs. Lay the coated oysters out on a tray and set aside until ready to cook.
Heat the oil in a deep fat fryer or large saucepan to 180C/350F. Cook the coated oysters in batches for 1-2 minutes or until golden-brown. Drain on kitchen paper and keep warm. (CAUTION: hot oil can be dangerous; do not leave the pan unattended.)
Carve the salmon into slices and season with freshly ground black pepper. Serve with the beetroot salad, smoked mackerel pâté and oysters, with the granary bread and watercress alongside.