There is a specialized windscreen fillet tool in the Rover manual for installing the filler strip for the window seals, however they do not seem to be around anymore and even the vaguely similar replacements are very hard to locate. With a little blacksmithing a reasonable facsimile is possible to make. The main material in this case is galvanized steel wire from broken tomato frames. Cold forged flat and then bent into a diamond shape then affixed to a repurposed garden tool handle. It could likely be improved with some further adjustments but without it the task of inserting the filler strip in the seals would be quite daunting indeed.
