So, I have finished restoring the windscreen frame after I couldn't find a replacement. Its taken a long time and has been really quite tricky, the following pics show its progress but not sort of skimming through it.
Firstly, when we removed the screen from the cab this is what we were faced with...
I cut out the rotten sections and then through fabricating the form and welding in and then skimming with filler I was able to replicate the insert shape required for the screen rubber T section. This shows the screen when the repairs are done and its masked up and primed.
Next up, this is the screen surround with 3 top coats applied, its the same corner as that in the first pic so you can compare the repair. I was please with it.
Lastly, the screen in place, with the screen rubber fitted and the masking materials removed. It took an awful lot of work to actually fit the screen back in place. Due to the opening mechanism it has to be spaced in a certain way to get it level and to also make sure the seal comes into contact with the aperture.
The one issue we have is that screen rubber is smaller than the original, its the largest depth we can get on the market for this type of T section but in some places it only just reached the aperture so obviously wont seal too well. I may even just seal the top corners and just accept that we don't use it as an opening screen. Overall though if you consider its original condition when stripped I am more than happy with the result.