Variable List not available in Step 3 of creating a page from a template

[Mark Timperley]

I'm using a template so users can create new "Issue" pages as they need them. Each Issue is rated "High", "Medium" or "Low" so I used a Variable with that List of ratings to select from.

User can create a new issue page with a rating of "High" for example. However, later the user may want to change the rating to "Low" or "Medium". When they edit the page, the list is no longer available (it's only available in Step 2: Fill in template variables). How do I provide a dropdown list (i.e. select in HTML) for users to select from when editing the page?

[Mark Timperley]

I've tried adding an HTML Macro, and this allows the user to make a selection, but I'm not sure how to update the page with the selected value. For example, my HTML is:

and it renders like this

but after selecting a value it is obviously not retained... I'm not sure how to pass this value back to Confluence so it is saved on this page.