Hey @Gavin_Attard,
Meanwhile, the answer about the KNIME project arrives. If you want to keep the interactive mode within the Google Authenticator node, you can use your own Google Cloud console project by selecting “Show advanced settings” and then flagging “Use custom client ID.” in the node configuration dialogue .This will “charge” the API requests directly to your project, impacting your own quota. 
To do this, you need first:
-
To create an OAuth Client ID (Desktop application) in your Google Cloud Console project and download it.
-
Enable the Google Analytics API, or the API that you need to use, in your Google Cloud project.
Then it is possible to download the JSON file to your local system or put it in some KNIME Hub instance with execution capabilities.
For example if you choose “Local File System” you need to provide the path where the JSON file is saved in your computer, the JSON file looks like this
{"installed":
{"client_id":"your-client-id",
"project_id":"your-project-name",
"auth_uri":"https://accounts.google.com/o/oauth2/auth",
"token_uri":"https://oauth2.googleapis.com/token",
"auth_provider_x509_cert_url":"https://www.googleapis.com/oauth2/v1/certs",
"client_secret":"your-client-secret",
"redirect_uris":["http://localhost"]}
}
Otherwise it is possible also use your Google Cloud project by generating an API key from a Service Account as @hotzm suggested.
I hope this could be helpful somehow. 