What is the right course of action?

Your answer is completely correct. In this situation, you have the right of way to turn left. However, you need to allow the cyclist to pass first because they are already traveling straight through the intersection.

Forgoing your right of way to avoid blocking the junction is also important. Blocking the intersection can create traffic congestion and hazards, so it's good practice to wait until it's clear.

Turning left before the cyclist is not allowed because the cyclist is approaching from the opposite direction and going straight, so they have priority.

In summary, always yield to cyclists or other road users who are already crossing or going straight through before making your turn, and never block the junction. This ensures smooth and safe traffic flow.