Preheat the oven to 220C/430F (200C/390F fan). Cut potatoes into chunky chips. Place in a bowl, cover with water and leave to soak for 10 minutes.
Drain the chips well and pat dry with kitchen towel. Mix chips with extra virgin rapeseed oil, oregano, thyme, salt and pepper.
Spread on a baking tray in a single layer. Bake in the oven for 25 -30 mins.
To make the fish
If you pop the battered cod fillets on to cook now, following the packet instructions, they’ll be ready at the same time as the chips. You'll probably need to bake them in the oven for about 25 minutes.
To make the curry sauce
Heat the oil in a saucepan over a medium heat, add the shallots and fry until soft.
Add the garlic, ginger, apple and sweat for 2-3 minutes. Then add tomato puree, curry powder, flour and stir well.
Add water and the stock cube and give it a stir. Simmer for 10 minutes.
Liquidise slightly with a hand blender making sure to retain some texture. Season with salt and pepper to taste.
To make the mushy peas
Add the peas and tarragon to a pan of boiling water.
Bring back to the boil and simmer for 2 minutes, then drain. Add the butter, vinegar, chopped mint and stir to dissolve the butter.
Liquidise slightly with a hand blender making sure to retain some texture. Add salt and pepper, to taste.
To assemble
Cut the tops off the crusty rolls.
Hollow them out taking care to keep the sides in tact (you can freeze the bread you removed to use as breadcrumbs in a future recipe).
Put a spoonful of mushy peas into the base of each roll.
Stand a few chips in each roll.
Cut the fish into 2.5cm wide slices and arrange a few in each roll.