Sigh...so I sent out a couple of e-mails to my family in London letting them know of my plans and asking them if they had any advice. The one I expected to be most helpful was anything but...she said she waited a week to respond while trying to think of something positive to say, and ultimately ended up moaning that it's really hard to find jobs. (She did give the caveat that most of my family there are in the arts, so it's tough to find jobs in that area no matter what.) But aside from that...no actual, practical advice (other than to visit prior to moving, which I'm already planning).
I didn't really expect complete sunshine and roses ("Oh, you'll find a job in 5 minutes, and a place to live, it'll be great!") but at least some practical advice along with the doom and gloom would've been nice.