Two days ago I had a 15 inch crack appear in the windscreen starting from the top left corner and spreading down to the right. This was after that car had been parked in the open for 4 days during which the daily weather had changed from sunny and warm to cold and rainy. I noticed it shortly after driving away. I am not aware of any stones etc hitting the windscreen. The crack looks like it is internal to the glass ie. not on the inside or outside surfaces. Have booked it into Tesla Stratford to be done under warranty next Wednesday. How long do you think it will take to do?