Reminds me of a little battle I had with my daughters GT. I was trying to drop the headlining out and wanted to re-use it but I couldn't get the left side of the front bow out.

I battled with it for ages and couldn't imagine what the hell was causing the problem. It should have been as simple as the others, spring the bow up and disconnect one end, then the other. It eventually came out with such a rush it took me by complete surprise
It turned out there has been some welding done to the roof in the front corner and the plastic end of the bow had melted and wouldn't extract from the hole!

Incidentally NZ (UK sourced) cars had colour coded plastic ends and, from a post above, Aussie ones might be painted.
Regards
Al