Okay, so I have manually upgraded to v6.1.5 and I can see the database now has some issues - this was to be expected.
However, I wasn’t expecting the link to a "database checker tool" to be just a link to a discussion elsewhere and the comments by Al Brookbanks aren’t much help... “Please use a tool such as phpMyAdmin to make any required changes” ... erm, yes, so how exactly?
There appear to be two types of error message.
This is what I am looking at:
CubeCart_admin_users.adm