Many thanks for such a quick response.
Possibly what you suggest would work, but I am looking for a one button solution that does not require me to write any YAML in my script at all: I just want to amend some standing template.
The main thing that is bugging me is that the MSWord template assumes US Letter page size, and, being based to the east of the Atlantic Ocean, I want my pages to be A4. So I am looking to edit some MSWord template that must surely be in a file somewhere so that I do not have to think about the question again. As matters stand I have to 'duplicate' the MSWord document, delete its predecessor, change the page size, and save it again.