They're independent, aren't they. The St Patricks one is in a tiny road off Oxford Street in central London and I can't say I've ever noticed it, though I've been based at colleges round here for years. Seems odd to have all their degrees validated by different UK unis.
Personally, I would only teach at colleges like that if I really needed the money, though my subject wouldn't fit anyway, as they seem to be more industry-orientated in their range of courses. I know there are certain places I *should* teach at for career enhancing purposes, if that doesn't sound too pretentious, though those colleges would also be far more interesting academically for my topic.