So if you are in a situation like this, simply stop the car:
‘In front of the opposite street, before the centre line of the other road’
And after giving way to the straight car, finish your turn.
What if there are cars behind us? Don’t we block them by stopping in the middle of the road?
No. The reason we get slightly closer to the centre line is to leave some room on our left, so the cars can go to our left and pass us.
They can do that if there is enough room for them. If there is not enough room, they will stop behind us and wait for us to finish our turn, then they will go.