bill - 1:30 am on Oct 6, 2009 (gmt 0)

That's really odd because Opera is my only browser that works correctly with Google and Bing for me in Japan. FF, IE and Chrome are always giving me the Japanese version of the SE. I have to use the browser, go the the preferred version of the SE, and then the search box will work correctly.

Are you logged in to Google when performing these searches? Have you set your preferences there?

In Opera have you tried deleting the problematic SEs and then manually re-adding them by right-clicking in the search box of your preferred language version of the SE?