I have a sneaking suspicion that I may have messed up here. I was just looking at an Asterisk 11 machine, and that was reporting pjsip being there, and chan_sip listening on port 5061, like that. So I'll have a look at that tomorrow and see if I can figure out what the problem is there.
There's still an ongoing 'Service is crashing and I don't know why' problem, so I'm going to put it in a wrapper that'll love it and hug it and log errors to somewhere sensible 