Well I just tried it - and it appears to work. And I'm a 'us' user..
[balay@n-gage ~]$ fetchyahoo Logging in securely via SSL as myusername on Fri Nov 12 10:53:28 2004 You are using 0% of your 100.0MB limit. Successfully logged in as myusername. Country code : us Folder: Inbox Version: 2.8.4 Getting Message ID(s) for message(s) 1 - 1. Got 1 Message IDs . Finished downloading 1 messages. 1 message(s) have been deleted.
You're using 2.8.4; the problem only appears to have manifested itself in 2.8.6. Could you try upgrading and see if it still works for a non-uk user?
Paul.