Ignore me about the custom fields.
My reposter has since died (3 days ago, to be precise!)
In fact even auto posts no longer work.
I reset the reposter again a few days ago and – touch wood – it looks like all the newly reposted articles are having that field set now.
The issue now is all the older articles that I’ve tagged to be ignored. If I remove those tags, the reposter jumps back to repost them instead of continuing in sequence.
I’m wondering if there’s a way to spoof the custom ID’s value…?