Put the thin rashers of bacon between two baking trays and bake for 10–15 minutes, until the bacon is really crispy and flat. Set aside.
Melt the butter in a heavy-based saucepan over a medium-low heat and fry the fennel, carrot, celeriac, celery and half the pancetta together until soft. Add the cabbage and pour in the wine. Cook until the wine has evaporated, season with salt and pepper and set aside.
Heat the chicken stock in a saucepan over a medium heat and add the remaining pancetta and tarragon and heat through until the pancetta is cooked. Strain through a sieve, reserve the stock and season with salt and pepper. Discard the pancetta and tarragon.
Heat the oil in a frying pan over a medium-high heat and sauté the scallops until golden-brown. Squeeze the lemon juice into the pan, along with a knob of butter and a sprig of thyme. Baste the scallops and set aside.
To serve, divide the cabbage between two wide bowls, top with the scallops, pour over some stock, garnish with basil leaves and snap over some bacon shards.