Preheat the oven 350ºF. Line an 8” square baking pan with baking parchment or spray with nonstick spray. Set aside.
Add the oats, flour, sugar, bicarbonate of soda and sea salt to a large bowl and mix to combine.
Pour in the melted butter and mix until all the ingredients in the bowl are completely coated with the butter.
Put 2/3rds of the crust into the prepared baking pan. Use a spatula to press it down. With clean hands, use your fingers to press the mixture into an even layer. The warmth from your hands will make the process easier.
Put the pan into the preheated oven for 10 minutes.
Meanwhile, make the caramel by putting the unwrapped soft caramels and heavy cream into a small saucepan set over a low heat. Stir continuously with a wooden spoon until the caramels have melted. Remove from the heat and reserve 2 tablespoons of the caramel sauce into a separate bowl (you will use this for drizzling later). Set the caramel aside for now.
When the base of the Carmelitas has had 10 minutes in the oven, take the pan out and sprinkle over the chocolate chips and chopped chocolate.
Pour the caramel in an even layer over the top. Spoon the remaining oats and flour mixture on top, press down gently.
Return the pan to the oven and bake for 15 minutes or until the Carmelitas are a light golden brown.
Remove from the oven and leave to set in the pan for an hour or so. Turn the Carmelitas out and use a sharp knife to cut into 12 equal squares.
Drizzle over the reserved caramel and serve.