The blinds for UPVC windows once fitted are excellent. However, because we are instructed to measure the glass it does not take into account a) the slightly protruding rim of the frame or b) the slight variation of 5mm at the top compared to the bottom of the glass pane because of the age of the house. I rang to get some advice which wasn’t adequate. I should have been told to take the smaller measurement, whereas I took the larger. Consequently, not one of the three frames fitted. We had to cut off a small piece of metal from each frame and had a real battle getting the frames to clip to the window. Once we succeeded they look amazingly good. Simple directions are all very well but a bit more guidance and information is needed at the measuring stage. I am very hands on and am used to these things, but I had difficulty.