Well by some means and thanks to the Eight Divines (but I prefer Talos be included ) I've managed to get my game to load and play for an hour or so....just until it CTD'ed. I would have reloaded but it was so cold here in the early hours (even with a heater on) I had to forego continuing because my fingers were cramping up with the cold. A CTD is OK though as I much prefer a crash to desktop than constant freezing. Not to mention corrupt saves.
I have all my saves backed up, although I don't keep all of them otherwise I'd have a folder with GB's of saves. But, I found one lonely Autosave that worked from a few levels back when I launched the game via the Skyrim launcher by mistake instead of with SKSE, and it detected my system settings again. I let it create the new ini settings so Auto saves were still on, until I changed it as soon as I got in the game, but it did have time to make one...the lucky one it seems.
Suffice to say I may be able to continue and I made a number of new hard saves (that are working so far) just in case since all the others are useless.
This time I've increased the difficulty from Adept to Expert because I'm just one hitting everything at level 52 which is no fun at all, (except Deadly Dragons!)but it doesn't seem to be any harder. Next playthrough I'm going to invest in some mods that reduce the fast leveling and make the game a bit more challenging, as well as trying out Master difficulty, but I'll try to finish with this character first. If I add anything to her mod list, or heaven forbid remove any mods which can be worse, I'm afraid it will break the fragile status quo.
A week or so away from the game makes one appreciate just how beautiful the world is though when you're not seeing it all the time. Like the old saying..."Absence make the heart grow fonder."
No-one can say I'm not persistent. And I didn't have to reinstall which would have been a pain. Must be the luck of the Irish and determination to not let these things beat me.