You’re right I was missing the action mappings in the configuration for the WCF Port.
If anyone else struggles with this then go to the send port properties, click on the configure button next to the protocol drop down and enter the operation mappings in the SOAP action box. There is an example there, but you can get the actual mappings for your service from the binding XML file that was generated by the Add WCF service function. The xml will be encoded in one of the XML files generated by VS.