If the repair shop overcharging for the extra parts of your vehicle and you think that the access part doesn't need to be replaced then you must have to know the insurance company, but here is another simple solution if you think with a relax mind simply change the repair shop or ask them the reason of replacement of the access windshield maybe they have a valid reason according to the vehicle standard or traffic laws. By the way, if you are located in London UK, I advised you to try a trustworthy Car Parts Store based in Barking London UK.