Pre-heat oven to 180c.
To make breadcrumbs: Tear the bread into pieces and drop into a food processor with a blade attachment. Add flavourings and seasoning. Pulse the bread pieces until crumbly - for fine breadcrumbs pulse more. Spread crumbs on a large baking tray and transfer to oven for 15-20 minutes; stir occasionally until crumbs are pale golden and lightly crunchy. Taste and add additional seasonings as you like. Set aside to cool.
To make tartare: In a small bowl mix all the ingredients. Keep in fridge until ready to use.
Place fish fillets on a flat tray and pat dry with kitchen paper. Place the flour on a plate and season with salt and pepper. Lightly whisk the egg and milk together in a shallow bowl. Put 1/3 of the toasted breadcrumbs on a separate plate.
Dip both sides of each fish piece in the flour, tapping away excess flour. Dip both sides in the egg mix then coat thoroughly with the breadcrumbs. Place fish on the lined tray. Repeat with remaining fish. Add more breadcrumbs if necessary. Chill for 30 minutes before cooking.
Melt half the butter with half the olive oil in a large frying pan. Once little bubbles appear add the crumbed fish fillets and cook for two to three minutes on each side until crispy, golden and cooked through. Drain on kitchen paper. Serve with Cucumber Tartare and seasonal vegetables, or green salad with a wedge of lemon.