Getting rid of 2.8

[bonnevie]

I had to leave for a few days, but I will certainly try what is shown in this video later this week . I won't reinstall until there's no hope. Thanks again for your help.  I know this should normally be pretty straightforward.
As for my original attempt, at first I couldn't "stretch" my LL3 partition. Nothing was happening when I was trying to pull the colored side to the left or use the black arrows on the partition. As I was stuck, I saved a slightly modified partition, retry and on my second attempt, the partition bar did extended all the way.  I think that may have caused this problem.