Hmm, have you checked this thread at Codemasters website?
In short, you need to know the IP address of the computer, where you run the Telemetry tool. Then you make the game to send the UDP traffic to that IP address. If you are not sure, the installation of the Telemetry Tool works ok, you could use the FeedTester (see in the ReadMe.txt) to ensure that at least the tool receives data.
Got it all working thank you!
I was putting the wrong IP Address into my Xbox, i did say i didn't really know what i was doing xD
This application is brilliant mate thank you! Just noticed an issue when trying to open a reference lap though, everything appears as a flat line as apposed to correct read outs?