I had my S1 windscreen replaced on the insurance about 6 weeks ago.
I had a smallish chip on the upper right, about 6" from the passenger side A pillar. I took it down to get repaired and they outright refused to touch it because they felt it was too close to the side of the screen, and might split if they injected resin into it. The guy advised me to just get my moneys worth out of it until it finally cracked, and the previous owner told me it had passed the last vehicle test with the chip present, as it was nowhere near the driver's field of view.
I was happy enough with that, and planned to eventually replace it one day. Then a few weeks later one very sunny sunday morning I came out of the house and the car looked grand. 30 mins later Leanne came in and said "S*** theres a huge crack across your windscreen!". Sure enough, the heat had caused it to crack from the passenger side to the centre of the screen. The next morning when I left for work it had reached 3/4 of the way across, and by the end of work that night its journey from one side of the screen to the other was 100% complete!
I got it replaced on the insurance, with what translates to roughly £60 excess. I was at work when the guy called out to the house, and I was wary of them doing a bad job because I'd seen someone who had aftermarket trim fitted (Lez I think), and it didn't look too good. I'd heard the stories about it.
The windscreen guy had been on the phone to his depot and they said they had one XM trim left in stock. He went to get it only to discover that it had been warped out of shape and was unusable. Unsure of what to do, Leanne rang me and I reluctantly said that he could fit the aftermarket trim if nothing else was available. Fortunately though, the guy reckoned he could rescue the original trim and reuse it.
Sure enough, he spent about two hours extra painstakingly extracting the trim and it went back on with the new screen, a perfect fit. I made sure to bung him 50 quid for his own pocket for all the trouble he went to.
He told me that only a few people in his company had done XMs and the trims were notoriously hard to get, so really he'd done me a real favour. I just hope I get him if I ever need to use them again.
So seemingly the trim can be rescued if your patient. I wish I'd been present to wittness what he did so I could offer a bit more advice on it

Ciarán