"isn't it at least just as strange that the Users Guide (and other places in the Help section I looked, there's no attempt to say how this sort of thing is managed?"
Hi Peter,
Page 249, Numbers '09 User Guide, located by searching 'delete file':
Saving a Custom Template
You can save your new template so that it appears in the Template Chooser.
To save a custom template:
- 1 Choose File > “Save as Template.”
- 2 Type a name for the template.
- 3 Make sure the folder named My Templates appears in the Where pop-up menu of the Save window.
The template is saved in your home folder in the following subfolder structure: Library/ Application Support/iWork/Numbers/Templates/My Templates/. It appears in the My Templates pane of the Template Chooser.
- 4 Click Save.
To delete a custom template, in the Finder navigate to the folder in which you saved the template, and drag the template to the Trash.
(Emphasis—bold italics—added)
What's missing is information on the location of "the folder in which you saved the template," and how to get there if that location is your (user) Library.
The addition of the option key requirement to reach the (User) Library was added with OS X v10.7 (Lion). As Ian notes, it takes a while for the documentation to catch up.
(You'll also find the option key is key to reaching Save As... in Numbers, Pages, and other applications following Apple's current practices.)
Regards,
Barry