Cut out the trunk pan.
The cut out trunk pan:
Note the the upper corners. I had to cut slightly differently than what I planned, as underneath there is part of another panel that overlaps right in the corner, so I had to avoid cutting this.
To maintain structural integrity, a strip of the trunk pan which is spot-welded on top of the box section was not removed, also some of the pan was left where it meets the tail panel, and about a foot or so of it remains where the pan meets with the back seat. Also, cut away some of the pan to one side of the box section. Will finish the other side tomorrow as well as neatening some of the cuts (straightening them out) to make it easier to cut the new panel to shape.
It’s a little weird being able to see straight through the car now.