Well I admit defeat. Been through any number of online forums supposedly dealing with the frustrated update issue to no avail. The machine won't run SFC or dsim, or do a repair/ partial install of Windows 10 from media creator. Looking at the event viewer error log issue seems to have started in December. I did manage to juice the WiFi adapter driver somehow, cured by unticking a ' jumpstart' box in the connection settings ( how did that get there?), that at least was a helpful suggestion off the web, couldn't bind the TCP/IP stack of some such thing.
Judging by the number of posts online, seems to be a widespread issue with the hint that it might be AMD machines mostly. All I need now is for Microsoft to stop telling me my machine may be at risk as it isn't up to date. Cheers for that.