Thanks for the quick response!
I’ve tried some of the basics outlined the Custom Fields tutorial but that doesn’t get me far enough. Perhaps I’m not as clever with coding as I’d like to think sometimes, but things are a bit complicated by the theme I’m using.
[url=https://atlanticsentinel.com/]Here’s my site[/url]. The theme I’m using is “Arras”. The whole of the postheader seems to be defined in library/filters.php and I’m not sure how I can make a specific custom field show up alongside there.