p/n: 31414200 You can get them from your local dealer or online. I ordered replacements when I ordered some other parts and accessories online for a better price than the local dealer. (Maybe order replacement wiper refills and the clips at the same time for a discounted price.)
One of the clips in the cabin, or in the boot?
I lost one in the boot, it fell in the rectangular air ventilation grille when I took the shade off.
I could see it with the help of a torch and eventualy got it out with a long wire and some double sided tape.
Took some fishing though
Now I cover the vent when I take off the shades...