This job is very straightforward. Best of it all, you always have the spare actuator available to you can see where to put stuff.
I did this in about 1 hour, and did break some stuff. Or, what I broke was the 2 things that held an electric wire to the actuator. They hold a wire in place, so I just used some elastic silicone as a replacement.
Anyhow, I could get the actuator out without messing with the window or the door lock thingie on the outside of the door.
It took about 5 minutes of cussing to get it out, but eventually I found a way to slide it out. I did have to unscrew the guidance for the wire that rolls the window up or down. Then I could slide the actuator.
See the photo I borrowed from the OP.
If you unscrew that guidance in the bottom so you can push it inwards, and just loosen it at the top, you'll get the actuator out through the lower section.
As for disconnecting the window, I just unscrewed the actuatuor and with my hand, I could disconnect the rubber spongy thing attached to the window.
It was farily easy to get it back in place, the window thing I mean.
So there should be no need to remove the window or anything on the outside of the door.
Cheers and thanks to the Op, since I probably just would have let Bmw fix it if I hadn't found this DIY.