Mark1, there is an easy way to check which servers you trade through. When using the brower based TWS version open the Java console panel and check the server address which is shown pretty much in the beginning. Alternatively, when using the standalone version, you can check by having a look at the log.txt file (I think that is the name of the file) within your TWS folder. There it is specified which servers TWS connected to. Also, you can check the .ini file which will be changed after a successful login regarless of what you entered in there in the first way.
Another possibility to check what server you are on: Open a DOS-box, type "Netstat / a" (without the "s of course) and then you should see a list of connections, among them gw1.ibllc.com or gw5.ibllc.com (the HK server will show another number). Regards Bernd Kuerbs