Pre-heat the oven to 220 degrees. Heat the vegetable oil in a large, heavy-based saucepan to 180 degrees. Place the herbs, seasoning and the mayonnaise in a food processor and pulse until you have a smooth green herb mayonnaise.
Spoon into a small mixing bowl, cover and chill until needed. Arrange the chips in an even layer on a baking tray. Bake for 20-25 minutes until golden brown and crisp on the outside. Meanwhile, season the fish and cover in the flour, shaking off any excess.
Coat carefully in the breadcrumbs and deep-fry one at a time in the oil for 3-4 minutes until golden brown and crispy on the outside.
Line serving plates with nonstick baking paper and sit the chips and fish on top, seasoning with salt. Spoon the mayonnaise into 4 serving pots and place alongside the fish. Garnish with the lemon halves and serve immediately.