There is another forum use I wish to block. The only button I can find to do so is buried on their profile itself, a 'report/block' button, which opens a page with two block tickboxes that don't seem to do anything permanent (refreshing the page after ticking them unticks them). I do not wish to 'report' this person, just quickly remove them from my social circle.

Skimming through recent threads, I see that the block feature has recently been revised? And that blocked users can see posts by the people who have blocked them? Is that for real?

I'm posting this here as I could not find a site admin / nuts & bolts forum.

The group you're looking for is UMD Dev, here:
https://umd.net/groups/group/umd-development

This thread in particular may be of relevance:
https://umd.net/groups/recommendation-to-update-blocking

I'll flag this thread to MM. Blocking is something that's come up a few times recently.

There is also the option to raise a Bug Report for things that don't appear to work as they should, open the "Home" meny and it's one of the options under "Contact Us".

Please click the blue button to submit the form. The text field is optional. The form looks like that because it's a common form used for many things, including Contact Us, Piracy Tips, etc and reusing code is essential when I'm the only programmer. But I'll be putting in work over the long-term to make it more obvious that the "block user" checkbox does indeed block people, but at this time it is already in working order.

Meanwhile, if you want, you can contact me regarding this person you'd like to block. Just use the... Contact Us form Or you can message me directly. I'll check your inbox and chat logs to see if I can go ahead and identify who this person is, and see if they are impacting anyone else on the site.