Not cheap either but I went with: https://www.boot-buddy.com as they were down the road and custom fitted mine. What I like is that it’s a ‘box within a box’ so when seats are down, the ‘outer’ box just slides out and covers all the exposed areas. Other things I like
– it is full overage up to the doors and over the folded back seat
– it’s plastic (well poly something) so super strong and very easy to clean, take it out, hose it down, put it back
– doesn’t use velcro as it’s stiff enough
– bunch of nice fellas in Worcester who design, cut, install while you have a cup of tea and a chat. Couldn’t have been more helpful
What I like less is
– as it’s stuff it doesn’t contour over the wheel arches as per your pic. So you lose a bit of space
Keeps the boot clean with all my cruddy MTB in and if I don’t want to take bike on the trailer then it’s brilliant for keeping the whole inside of the car clean. When I gave my Yeti back after three years of blankets and best efforts, took me blooming ages to clean it up enough to pass inspection.