How do you replace the drivers side rear wheel arch liner on a 2003 Octavia?

It should be quite simple to do - it just screws in from underneath using lots of torx screws (about 12 if I recall correctly)

Take the wheel off first

I recently managed to replace a passenger side one with the wheel in situ! Took a bit of squeezing into small gaps, but I did it! I would have taken the wheel off, but don't have anything other than the standard jack for keeping the car in the air...