Bottom line IT'S FIXED!!! I'm running 1803
The low point was that after the remote installation from ISO I lost some basics like the start options, notifications, and the ability to chat/request call back from Microsoft. Oh and still at 1709.
DSIM showed corrupted files.
Next day contacted Microsoft again from another PC (My reliable old Windows 7 machine) and we started again. This time I was passed to level 2.
After another failed attempt from ISO the LVL2 guy went for a full Windows 10 reinstall.
I'm now reinstalling Office and other apps so it was quite disruptive. My files are still OK. and the apps are all in Windows.old.
I can't really say what the problem was but I watched the LVL2 guy search and find the word "rollback" in the log file. Just above that it was checking drivers. But i think I also had corrupted files from repeated failures to install.
I should add that Microsoft remote support was involved with me for 6 hours elapse time yesterday and a further 6 hours today.
I would like to say thanks to the support guys but still feel the same way as before about the way Microsoft imposed this grief on me in the first place.