@InsanePete in your Output Log (different from message log) in the bottom left of UEFN you should see the same errors after running validation as you do in the message log.
Above those red errors you should see log lines pointing to .uasset files. If you copy just the names of the .uasset files (Exclude the .uasset part) and paste them into your outliner you should see which actors are causing the issue. Hope this helps! Thanks.