What should you note when driving a car after coupling a trailer caravan to it?

You answered correctly. When you attach a trailer caravan to your car, two main changes happen: First, your vehicle becomes longer, so it takes more time and distance to overtake safely. Second, the combined weight of the car and trailer reduces the car's acceleration ability, meaning you speed up more slowly. The idea that the necessary cornering radius is reduced is incorrect; in reality, you often need a wider radius when turning with a trailer to prevent the trailer from hitting the curb or cutting the corner. Remember these effects each time you drive with a trailer: overtaking takes longer, acceleration is slower, and turns often require more space.