I know it was a wrong decision and here's the proof.
1. Here is a composite view, made from a series of shots from the camera behind the posts. As the ball went way over the posts, I have added a green extended post.
I do not think there is any doubt, at all, that the ball is at all times within the posts, it doesn't deviate, it doesn't swerve away from the posts, it is a drop goal.
I should add that the camera is very slightly to the left of the ball's trajectory. The ball travels in a parabola. This means that viewed from the camera, it will appear to travel in a very tight parabola from left to right, which explains the very slight impression of a "drift" to the left - but that is an optical artefact, and not an actual drift.
2. With regard to the footage from the other direction, I have frozen and enlarged the moment where the ball hit the glass on the boxes behind the post, just underneath the sign that says "FANTASTIC MEDIA STAND".
The green arrow in the zoomed in section shows the ball hitting the glass.
The green arrow on the lower image is the shot posted a couple of pages back. The ball is not on this shot, (because the BBC cut the shot before the ball landed) but the green arrow points to the spot the ball struck, as evidenced by the previous image.
The ball did not drift to the left. It actually landed almost centrally behind the posts, the blue section of seats where it lands is 16 seats wide, and the ball landed in the 10th seat as viewed from L to R on the image. Here is an image of the ball landing, with a very enlarged spot showing teh position of the ball, indicated by the arrows I have added.
Whilst this may look blurry, if you view the footage (which is on iPlayer) you will be in no doubt at all that that is the ball.
I rest my case.