The 25mm aluminium flyscreen frame material that Bunnings sell has a width of 11mm. (The side that goes in the channel around the window). The channel is 11mm wide on the ouside mesurements. The inside has a ridge making it approx 10.5 mm wide. So the flyscreen width is too wide and won't fit. Is there a tool to adjust the frame aluminium down approx .5 mm. I have given it a small tap with a rubber mallet and this makes it fit. Not the ideal solution..any Ideas..thank you.