weird, that is awful from Lexus. As pointed out you should have-
a) went through insurance and went to an authorised Lexus dealer to get it fixed.
I have been to hedge end and its fantastic and the attention i have received for merely ordering some parts is second to none. They would give you a proper hire car and not a stupid run about.
As for the pop up bonnet, I was not aware of the costs, I think insurance should subsidise repairs in this, after all its a safety mechanism, I don't see why the owner should foot a heftY bill for having this feature on a car in the first place.