For the Base Mayonnaise, use a stick mixer to blend egg yolks, Dijon mustard and lemon juice until creamy. With the mixer running on medium speed, gradually add grapeseed oil to egg yolk mixture until emulsified and reasonably firm in texture. Season with white pepper, to taste. Divide base mayonnaise evenly into two bowls and set aside.
For the Tartare Sauce, stir all ingredients through the half portion of base mayonnaise, season to taste and set aside in the fridge.
For the Garlic Aioli, cut garlic head in half lengthways and drizzle with oil, season and wrap in aluminium foil. Place on a baking tray and bake until soft, about 25-30 minutes. Remove garlic from oven and set aside to cool.
To finish, squeeze half of the cloves of garlic and blend through base mayonnaise portion. Add remaining cloves of garlic to taste and set aside in fridge.
For the Indonesian Dipping Sauce, mix ketjap manis and lime juice in a bowl. Add chilli, shallots, garlic and brown sugar and stir to combine. Set aside.
For the Pickle, heat vinegar, sugar and 90ml of water in a small saucepan over medium heat, stirring occasionally until dissolved. Remove from heat and set aside to cool.
Meanwhile, place sliced fennel, fronds and shallots in a bowl, pour cooled pickling liquid over sliced vegetables and set aside.
For the Thrice Cooked Chips, place a large pot of salted water over high heat and bring to the boil. Add potatoes and boil until cooked through, but not broken down, about 15-17 minutes.
Drain potatoes well in a colander and place onto a cooling rack in the freezer for 20 minutes.
Place vegetable oil into deep fryer or large deep saucepan and heat to 150C. Remove potatoes from freezer and deep fry until light golden, about 5 -7 minutes. Remove from deep fryer, place onto cooling rack and back into the freezer while preparing fish.
Heat oil to 190C.
For the Ginger Beer Battered Flathead, cut fillets into quarters. Lightly dust fish pieces in extra potato starch and set aside in fridge.
Mix all dry ingredients together in a medium bowl. Using a stand up mixer, whisk egg whites until soft peaks form and gently fold through dry ingredients, careful not to knock out too much air. Pour in ginger beer and fold through batter.
Working quickly, dip fish pieces in batter to coat and place into oil, 2 pieces at a time. Use a small spider to move the fish pieces around and ensure even cooking. Cook until golden brown, about 2-3 minutes.
Remove fish from fryer and place on paper towel to remove excess oil. Season with salt and set aside.
Remove potatoes from freezer and deep fry until very crispy, remove from fryer and drain well. Season and toss through salt to taste.
To serve, place some chips and fish onto serving plate. Add some of the pickle and each sauce in separate ramekins onto the plate. Garnish with lemon and lime cheeks.