Preheat oven to 200 ºC.
Combine sherry, brandy, garlic, 3 bay leaves, tarragon, juniper, ginger, allspice, salt and pepper in a large non-metallic bowl.
Add chicken livers, pork belly, cut into 1 cm cubes, and minced pork. Cover and marinate for 24 hours, turning occasionally.
Discard bay leaves. Add eggs and mix well.
Grease a 23 x 12 cm terrine or loaf tin and line the base and sides with bacon or fat, stretching them with the back of a knife if necessary. Leave the strips hanging over the edge of the terrine.
Put one third of marinated meat into terrine, followed by the chicken, cut into 5 x 2 cm strips.
Add another layer of meat, followed by gherkins and nuts. Top with remaining meat.
Fold over the bacon to enclose the terrine and decorate with remaining 6 fresh bay leaves.
Cover with aluminium foil and put terrine in a baking tin filled with boiling water to come halfway up the sides of the terrine.
Bake in preheated oven for about 2 hours.
Test, to see if it's done, then remove from the oven and allow to cool.
Cover and refrigerate until ready to serve.