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 dredge 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 greaseproof 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.