I have that graphics driver(8.15.10.2697 WDDM 1.1). Needed it myself for a dell inspirion. Let me know if you should change your mind about win10. I, too, would like to see you come back.
What 8.1 version you use? If you use an Pro VL and have activated MTK2.x or any other not 100% legit activation, WU may not 'shows' up!