Wow, that is shocking!!
Well, since I asked the question, I remembered that I still had a bottle of silver touch-up paint (from my previous reflex-silver MK8), and I dabbed a tiny bit of that onto the trim... and its 95% fine now tbh!
You'd definitely need to be looking hard for it to spot it, so I don't think I'll be asking the dealers to rip the dashboard asunder to replace it.
I also think I may have caused the problem in the first place. I didn't have the car long when I realised that if you remove the rubber mat from that cubby, then your phone fits much better and charges more reliably. But, I believe there's always air blowing from that cubby (to cool the phone) and I'm thinking maybe that stream of air caused the paint on that strip to lift a bit. Just a theory... I've refitted the rubber mat now anyway.
