It does seem like the folder is very slowly growing in size, up to about 8gb now. My original database on the legacy version is about 70gb so a way to go yet (if it is actually downloading it all again?).
I also tested how much is downloaded by turning off the internet connection on the laptop. Most notes were 'download incomplete' . Most of my notes are screenclips and I have many thousands of them (60,000)- so I guess I'll have to leave the computer syncing a for a few days. Hopefully this solves the original tagging problem too (not all tagged notes coming up).
Must admit I am quite surprised at how slow the new version is to open a note, even when that note is 'downloaded'. The top part of the image opens and the rest 'scrolls' open over a second or two. Was instant in previous version. In fact the whole ver 10 program seems very slow - opening, scrolling, moving through it etc. I've noticed this with the android and ios versions as well that i use on other devices. Anyway I'll wait to see what happens in a few days - hopefully everything is 'downloaded', works as it should and generally is back up to speed on windows laptop.