I believe I was able to recreate this on my end. I think you're out of luck short of a change in the software. The ignore button isn't enabled when you don't have a subscription to the "hinted" record.

As for the search results, that seems to work pretty well for me excluding non-American. Can you verify that you have collection priority = "UK and Irish" and "Show only records from these collections" = Yes (ticked)? If you're still seeing American records with those settings, you might have stumbled onto a bug.