I had this problem just a week ago mate.
Do this before you settle down for the night, dont go back to car until morning.
1) Turn your engine on and leave the heaters (full on front window.
2) clean the window with warm soapy water, really press hard and rub it.
3) Then dry the window with a dishtowel before the soapy water drys away.
4) Then put 3 blobs one at top and two bottom (triangle effect).
5) Use the spacer with the top one and then stik another blob on that. HOLD THE HOLDER ABOVE THE HEATERS FOR A COUPLE OF MIN BEFORE STICKING IT ON, STIKY BITS FACING DOWN. (sorry forgot to mention that).
6) Face the holder face out and stick to the window, press hardish for 2min.
7)Leave the heaters on for another 10min then cut off.
8) wake up next day with the holder stuck hard as fook to the window.
It worked with me mate and i never thot it would.
Try it and see how you get on.