Unchecked the box, and it does appear. But now I can't get it to go away on the front page, short of deleting the tag altogether from the posts.
Would that be the Tag or the Featured content section?
The box labelled
[ ] Don’t display tag on front end
at the bottom of the Featured Content accordion.
Ticking or unticking the checkbox now makes no difference, either in preview in Customize, or after saving change and reloading the front page.
Assuming you mean the 'Don't display tag on front end' then this only controls the Tag output in the tag cloud or under the post in the blog feed if the options to show Featured content in blog feed is selected. Or are we talking about a different checkbox?
Looks as if I misunderstood the purpose of this tag.
So where do I turn on or off the inclusion of a Featured Post on the front page?
Please provide a link to the site as a closer inspection of the site's source code usually helps debug the issue.
It's still very much a temporary website 'in draft' and under constant development for the next two or three weeks. But you can see it at http://kiidstrust.dyndns.org - the final site will move to a permanent url later.