Preheat the oven to 140°C.
In a bowl mix 3 tablespoons of the olive oil with the chopped thyme and a little salt and pepper. Brush the inside and outside of the trout with this flavoured oil.
Place the bay leaves, whole garlic cloves and lemon slices inside the fish. Place the fish on an oven tray lined with baking paper and bake in the oven for about 30 minutes until cooked.
In a bowl mix together the remaining oil, diced apple, chopped walnuts and lemon juice and season with salt and pepper.
Just before the trout is ready, heat a small frypan and cook the bacon for a few minutes.
Carefully transfer the trout to a serving platter. Spoon a little of the apple and walnut preparation on top and sprinkle with pieces of bacon and chives.