I'm trying to remove the side rails for the false boot bottom in my superb. I have attached a photo of what I believe to be the release mechanism. I presume I turn it one way or another but I cannot get it to budge. Can anyone give me more information on this?

If it the same as on my Octavia it should rotate clockwise to release it. There is a steel lashing loop that the plastic clip covers and locates on. They can be stiff but if you press down on it had and then try to turn it it should move. Just hold the plastic by the edges as when released the metal loop is at 90 degrees to the plastic.

They can get stiff if left for a long time. Use a screwdriver through the loop to increase leverage. 

 

I must admit that I don't remember those on my previous estate.