Dear @MartinPoulter, thanks for contributing to Commons Impact Metrics! Apologies for the delay in updating you here; I was on vacation for part of last month.
However, the requested category has been added to the system normally, being available since the start of May, with data starting on April 1st.

If you need more information about CIM, here are some tips:

Commons Impact Metrics can be accessed via this page. It offers metrics for categories, media files, or users. You should add the category as "Memory_of_the_World_International_Register", with the underscores. The rest of the information requested is pretty straightforward (date, category-scope, wiki, etc).

We now have a portal on Wikimedia Commons, which can be accessed here: Commons:Commons Impact Metrics.

If you need it, there is this Diff post and this recording (minute 39:00) from a DPLA Webinar, in July 2024. And here are the slides for the presentation during the GLAM Global call.

Ways to use CIM:

1. This tool shows metrics more visually. However, your category might not be there already.

2. There is a way to offer views from CIM metrics on a Commons category. The Digital Public Library of America developed this:

Template:Views from category
Template:Views from category/table
Example: Category:Images from the Swedish National Heritage Board
Example: Category talk:Images from the Swedish National Heritage Board/Views

3. This dashboard, developed by the Biodiversity Heritage Library, offers some visualization options too.

We are finalizing a CIM-related training, but I hope this helps for now. Let me know if you have questions.