In this situation, should you signal the overtaking manoeuvre with the appropriate turn signal?

The recording shows that you intend to overtake a motorcyclist, which involves the need to change to the left lane. According to Art. 22 para. 5 of the Road Traffic Act, the driver of a vehicle is obliged to signal the intention to change lanes clearly and in advance. Therefore, before starting the manoeuvre, you must turn on the left turn signal.