Hunting down how to do this took far longer than actually doing it.
1. Run the Exchange Management Shell
2. At the prompt:
[PS] C:\Windows\system32>get-routingGroupConnector | ft name, guid
3. System responds with a list of Connectors by name and guid
4. At the prompt:
[PS] C:\Windows\system32>remove-routingGroupConnector <actual guid >
5. System responds with Y/N
6. Task accomplished, woot - at last.