For the fish, fill a deep-fat fryer or a large, deep, heavy-bottomed pan two-thirds full with vegetable oil. Heat the oil to 190C or until a breadcrumb sizzles and turns golden-brown when dropped into it (CAUTION: Hot oil can be dangerous. Don't leave unattended).
Sprinkle the flour onto a plate. Beat the eggs in a bowl. Sprinkle the panko breadcrumbs onto a separate plate. Dredge the fish in flour, dusting off any excess, then dip them in the egg, then roll in the breadcrumbs until coated.
Cook in the deep-fat fryer for 2-3 minutes until golden-brown.
For the tartare sauce, whisk the egg yolks and vinegar together in a bowl.
Continue to whisk the mixture and slowly pour in the rapeseed oil until all of the oil is incorporated and mixture is thick and light.
Stir in the capers, gherkins, shallot and herbs. Season, to taste, with salt and pepper and a squeeze of lemon juice.
Serve the fish goujons with the tartare sauce and lemon wedges.