In the hatch area the bottom cargo area seems to be removable, I can see a few bolts on the lift gate side when I remove the small panel on the floor, but are there any other bolts holding it down anywhere else?

And will I need to remove the rear side panels to get it out?

You have to remove the 2 rear side panels, the trim around the lift gate catch, and the carpeted trim part at the rear seats. You will be able to see all the attachment points then.