That was what I was looking for. I know it is silly and only save a few seconds but when I manually create an epub file I always add those values.
I have been able to add the additional tag entries to the New files created, no different to as if I had created them Manually (for example Author is
[Author name here]), I just don't have to.
I do have reasons for not using the other options but mostly it comes down to convenience for how I create/use the application and create files.
Save-As - tried that and it took longer than manually adding the 2 MetaData tags to the file (and I kept overwriting the template file)
Calibre messes with the format in ways I don't like much (although I have and do use it)
Thanks for the locations as that proved to be exactly that I was looking for