SpottyCat

If the glass is in the raised position, it shouldn't be in the way, unless I'm misunderstanding your comment? You will have the metal cantilever in the door space but that shouldn't be a huge obstacle. Even if you were to remove the glass, the motor is still bolted to the inside face of the door so will likely restrict access as well.

When I did replace the whole motor and lever section, I raised the glass, popped in a couple of wooden door wedges to hold the window and swapped the whole lot out pretty easily. When I refit the new one, I made sure to line up the bolts with the left over impressions on the brackets.

I put a copious amount of Dynax S50 on the inside of mine while I was in there too, for adding sound deadening, you could see about adding some on the reverse of the actual door card too? That way, you can test and adjust by popping it on and off as needed.