I changed the struts on my B8.5 Avant recently. There was a metal clip in the top of the strut. Looking closer on your pic it all appears to be plastic. Is that correct? It may just be a push fit. What’s the other end like? Is that the same?
Yeah, I've replaced several struts before, and they've all had a metal spring retaining clip that you would prise back to release the strut from the ball joint.
Everything on this one looks to be plastic though. Can't imagine it just being a push fit though. Too easy to dislodge the strut somehow when loading stuff into the boot IMO. I would think a locking mechanism of some description would be required for safety reasons.
Might be worth me contacting Stabilus for advice.