Caravan and Outdoor Life’s group publisher, Godfrey Castle’s, response:
It looks like this window has endured many days in the sun and so has become brittle with age. You mention “windows” – plural – so we presume it is happening to more than one window.
They are manufactured from acrylic, a type of plastic, and so your letter raises the issue of caravan
storage – your unit should be under cover and not in full sun, month after month.
I am afraid your windows have reached a stage where you can’t do anything but replace them with