Yes, he is clearly too impatient towards the learner driver. Full stop.
But to be fair, the marking is poor, as many people in the other forum state.
You have two lanes going into the roundabout which are marked (in UK-system) like if they are for going straight on (to Wingate Ct) or right (to Wellington Ave in the northeast), but only one lane exits at Wingate Ct. You could assume that the two lanes for "straight on" are marked for Wellington Ave going to the west because it wouldn't make sense to mark them both for one exit at Wingate Ct. Additionally, there is no "left-turning-arrow" when you enter the roundabout from Oberursel Way so if you follow the marking (and only them) you wouldn't be allowed to exit at Wellington Ave to the west.
If you come from Wellington Ave from the west or Wingate Ct you have left-turning arrows which indicate that you have to take the leftmost lane for first exit, that doesn't exist when you enter from Oberursel Way.
That said, I would be confused if I didn't learn to drive in the UK since over here there is no left-turning-arrow (right-turning-arrow for you wrong-side-drivers
) before a roundabout. In the end you are turning left, but technically you enter the roundabout in the other direction so you don't turn right.