Cal. 1481 Quick Set not functioning

Hi all - I'm new here and this is my first post.

I recently serviced my own Omega 166.0098 with a Cal. 1481 movement.

The quickset has never functioned.

I made a video of the refurb, and you can see the problem in the video.

Look at 6:10 in my video to see the problem.

The problem is not the stem.
I began by thinking the problem was the setting lever spring itself.
So I actually replaced the setting lever before I began to make this video.
I now have come back to again thinking the problem is the setting lever spring.
See how the arm that is supposed to push the little lever that advances the date ring is pressing against the movement plate.
I don't think that is right.
And the geometry of that arm is such that it is physically impossible to press it far enough in to get the date ring to advance.
I also noticed having a look on ebay that there seem to be two different designs for the setting lever spring, both part number 1480-1110.
The other design looks like this:
https://www.ebay.com.au/itm/205281316731
The arm is thicker and it has a slot instead of a hole to engage with the lever.

Anyone got any bright ideas?