Hi again, some feedback.
I tested in dev site, and then installed the latest VM and Joomla updates, and everything seems to be working fine.
I did notice however, that the VM Front Page menu item now has a (deprecated) warning and so in my dev site I tried the new VM setting, which is now recommended to be a Category Layout / Top Level Category menu item. On changing to this, it completely broke the site layout for that page - it just basically displays an index of the menu and not much more. (screen shot 1 attached)
I'm not too sure whether it has something to do with the way the menu item should be configured (I have tried, and don't seem to have any joy with that) or whether I should try to create a new Front Page Category 'holder' for the various shop categories and then select that. On searching the forums it seems that perhaps it has to do with the VM template overrides, and that something in the Flexible template needs to change to accommodate this.
For now, it's fine to keep the deprecated Front Page item on my live site, but perhaps you have some insight into how the newer version of the Front Page should best be accommodated. (screen shot 2 - deprecated Front Page menu item)
Thank you.