OK, just spoke to the service manager. He said categorically that they do not need to remove the engine mounting bolts during a cambelt change, as they can access the cambelt without doing this.
In case I had misunderstood, I confirmed this again at the end of the conversation, and again he repeated that they definitely do not remove them.
This seems to be contrary to what everyone else has said though.
He's going to get back to me when they have looked at the car.
Not sure where to go with this now. Whatever he now comes back with re the damage (and it could be huge), he's going to say it's absolutely nothing to do with the cambelt change.