The day got going before I was ready for it today. I woke up at 5 and 
couldn't get back off again. So here I am. I've got no idea whether 
anybody reads this (and there's no good reason why anyone should!) but 
if you do, I'd be glad to know. I had a response from the helpdesk - 
info on the sdf wiki about xmpp is out-of-date. If you want xmpp 
enabling, you need to send an email to membership requesting it. That 
might be a thing worth knowing.