Okay, Hijacking my thread back...
The insurance company has confirmed that they are rejecting the claim for my car. "Act of God", they're calling it. Therefore I've just got my own insurance company involved - wish I'd done so at the beginning, as these guys believe in customer service.
Anyhow, I'm getting yet another courtesy car next week. They're taking my own car away on Tuesday and have promised to give me a final decision on whether they will repair it or write it off within 14 days. Because they will be taking action against the original insurance company, they've warned me that it might take a while to get the financial side sorted out, but so long as I know for sure they're going to write off my existing car (and have taken it off the road - it's still sitting at my place, so still has to be insured and taxed), I can go buy a Benz and haggle the toss with them later.
I'm beginning to believe I might actually have the worst of this sorted out by the end of this month. Wish me luck!