Hi Neil,
I am Peter's colleague and will be following up on this thread as he is unavailable today. Since you are trying to exclude the IP address from campaign targeting, you will need to add that as a negative campaign criteria. Please refer
this sample code block. If you are still facing an issue please
enable the logging and share the SOAP request and response logs. Please use
reply privately to author option while sharing the logs.
Thanks,
Milind, AdWords API Team.