[Update 04/01/2014] Have switched over to new certificates. You should not get any errors about “self-signed certificates” any more and there should be no further interruptions of service.
I’m replacing the SSL certificates on both jabber.org.uk and xmpp.org.uk. This is to replace old self-signed certificate with certificates from a CA (Certificate Authority). It should eliminate any problems with self-signed certificates and increase your security of the service. This may cause some interruptions but hopefully all should switch over without too much problem.