Thanks @Curt. I have downloaded, installed and run this Debenu PDF Maximus FREE version, and it seems to work fine. (Shall trial it properly later, when I have the time.)
During install/registration, it wanted to phone home, so I allowed it through the Firewall as there seemed to be no "OpenCandy"-type issues.
This Debenu PDF Maximus FREE version tries to phone home each time you run the proggie, so I disabled that in the Firewall. There seems to be no settings menu in the GUI that allows you the option to disable phone-home actions.
This is a security/tracking issue: I am always suspicious of proggies that phone home by default, when there is no need to do so, and even more suspicious when they bury the option to switch it OFF inside a complex nest of menus (a typical old Microsoft trick in things like Media Player, for example), or - as in this case - give you no option at all so it is always fixed ON.