Technical 4x4 front arch trim

[Scass]

The arch trim of my Panda TA 4x4 is loose on the right side where it overlaps the under-door section of trim. When I peel it back a little, I see a fitting that does not seem consistent with what others have described in various posts here. There's a red plastic piece fitted to the body panel that looks like it clips in to the trim. I can't see any adhesive or double-sided tape, nor the plastic protrusions that others have attached using star washers. I wonder if anyone knows how these fittings work and how I can reattach the trim?

Thanks for any help.

By the way, this is not a UK model Panda. I'm in Portugal, so it is LHD and may differ from UK-registered vehicles in other ways...