Symantec control centre failing to synchronise with server

I've had an instance with Symantec's system centre not being able to show me the details of the client pc's, complaining that the parent server was down. An initial reboot of the server didn't fix the problem and most of the documents refer to reinstalling or upgrading symantec to fix the problem. However the document at Error: "Event ID 62: Symantec AntiVirus communications layer failed to initialize..." appears in the Windows Event Viewer - Application log asks for a restart of the service and changing the LoginCaCertIssueSerialNum registry entry - that did the trick.