Thank you Martin. Richard is wrong on both counts here. To replace a window in an Ultra takes little more than an hour. I have seen it being done. Renowns are under no circumstances, allowed to run in service with a broken window once it has been reported. He could not possibly have seen one driving around with no outer skin, as they must be returned to depot for repair. As you have quite rightly said, the glazing forms part of the body strength.