
Here's the two mounts side by side:

You can see how bulky the lower arm is on the OEM mount and that you need a lot of clearance to manoeuvre it.
I suspect that you're supposed to be able to pull the mount back a little, rotate the bracket clockwise, pivot it and pull it out in an upward motion.
On your own that's impossible if you can't get enough clearance on that inside lip that runs from the bottom of the bracket all the way to near the lowest mount bolt on the other side.
From an engineering point of view, the OEM bracket is incredibly sturdy but from a maintenance point of view it REALLY sucks.
That was a sh*t of a job which is now done and out of the way - changing the bushing will be simple in the future!