Preheat the oven to 200°C/fan 180°C/gas mark 6. Bring a pan of water to the boil and add the carrot, celeriac and sweet potato chips. Boil for 1 minute then drain and refresh under cold water.
Spread the chips on a large non-stick baking tray and drizzle with the oil, turning to coat. Season with freshly ground black pepper, then bake on the lower shelf of the oven for 40 minutes.
Meanwhile, spread the seasoned flour on a plate, pour the beaten egg into a shallow dish and mix the breadcrumbs and parmesan on a third plate. Pat the pollock dry with kitchen paper and dip each one in the seasoned flour, followed by the egg and then the breadcrumbs to coat.
Place the coated fish steaks on a baking tray lined with baking paper. Place the fish on the shelf above the chips and bake for 20 minutes, or until both are golden and cooked through.