Noise from cab windows

I have recently purchased a 2009 Autotrail its fab , however , there is a loud squeaking when the van is on the move, which is incredibly annoying ! I am pretty sure it is coming from the plastic mount holding the cab window blinds. It is not just in one corner but sounds like most of the panel moving against its fitting on the doors. I guess this is because of the age of the plastic (if it is plastic) . Is there anything I can put on the plastic to make it more supple or does anyone have any suggestions please . I am being put off driving any long distances because of it . Thank you