I have a T4 Navigator with a leaking window above the cab. I have removed the window and rotten wood, however the window is an old fashioned Perspex within a rubber seal design. I was wondering if anyone has replaced anything similar with an oversized piece of perspex bonded on from the outside? I have to rebuild the timber anyway so I can adapt it to any shape or thickness and at present if I retain the original window it requires a replacement seal. any advice or ideas would be greatly appreciated