@Barleyologist
Thank you for posting in Microsoft Q&A forum.
Here is a script written by Klaus Bilger, you may try it to see if it helps:
https://gallery.technet.microsoft.com/Check-SCCM-Distribution-e34b428e#content
If the response is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.