I have managed to get that working now. Thanks for your help.

The solution was as you said. I have a new file (.docx) in the Word Startup folder.

Then my template file (.dotm) in the same folder, runs autoexec() which opens the .docx. Gets the variable, does its stuff, saves it and then closes it.

In order to reset peoples choice, I just put the .docx in the source folder for the log-in script which will re-write the users local copy.