In the immortal words of professor Farnsworth; "Good news everybody!"

Okay - for the time being, I'm in - it seems to be running slower than usual but I'll try sort that out in time.
After multiple runs through Hiren's boot cd, Partition Wizard boot cd, and Paragon boot cds - I had poked just around everywhere in the registry, configs, boot partitions and whatnot. This post; Status: 0xc0000225 boot selection failed; required device inaccessible was pretty much the exact problem I was having.
Now - somewhere along the way (I suspect the paragon tool) it enabled UEFI for the DVD drive, and suddenly Windows boot manager picked up my alternative options by pressing F8

Safe mode failed but "Last known good configuration" suddenly worked - and that's how I got in a few minutes ago.

If that small bit of advice can ever help anyone else - then maybe it was worth the last 5 nights staying up until 2am.

Cheers all and thanks for your help.
I'm going to go make back ups of everything now just in case this happens again with the next update.

Also, thank God!