Not sure what, if anything, I did significantly different this time but after getting to the desktop and making some changes as before, such as DPI %, Deleting the Bottom panel, moving the Top panel to the Bottom, I then installed the "unoffical" package again and this time my modifications were immediately reflected in the Main Menu.
The only time something didn't immediately appear was when adding a Sub-menu which didn't yet have an Item associated with it.
Now, I'll have to revisit alacarte again in LXDE.
Hasta luego, Michael.