<?xml version="1.0" encoding="UTF-8"?>
<scr:component xmlns:scr="http://www.osgi.org/xmlns/scr/v1.1.0" immediate="true" name="Json Marshaller Service">
   <implementation class="uk.ac.diamond.json.JsonMarshaller"/>
    <service>
      <provide interface="org.eclipse.scanning.api.event.IEventConnectorService"/>
   </service>
</scr:component>

<?xml version="1.0" encoding="UTF-8"?>
<scr:component xmlns:scr="http://www.osgi.org/xmlns/scr/v1.1.0" immediate="true" name="Json Marshaller Service">
   <implementation class="uk.ac.diamond.json.JsonMarshaller"/>
    <service>
      <provide interface="uk.ac.diamond.json.api.IJsonMarshaller"/>
   </service>
</scr:component>

Correct interface reference in service definition
Correct interface reference in service definition

http://jira.diamond.ac.uk/browse/DATAACQTEAM-222