Why are you not allowed to overtake now?

Your answer is fully correct. The reasons you are not allowed to overtake here are:

1. The cyclist on the left could suddenly turn left, which means overtaking would be dangerous because you don't know their exact intention and would risk a collision.

2. You cannot see far enough ahead to judge if there is oncoming traffic. Good visibility is essential before overtaking, as you need enough time and distance to pass safely without causing danger.

This combination emphasizes that overtaking is unsafe both because of the cyclist’s potential maneuver and limited visibility of the road ahead. It's important to always ensure clear visibility of oncoming traffic and to consider the behavior of vulnerable road users like cyclists before overtaking.