I know you posted this a long time ago, but I've been working as a Probation Service Officer (basically a Probation Officer without the degree) for the last 3 months. It's blimmin hard work, especially as I work about 45 minutes drive away from home (but at least I don't risk bumping into any of my clients at the weekend!!). There is a lot of training to do. It's the best job I've ever had, to be honest, and it's great to do something I actually care about. It can be a bit risky, depending on what type of people you work with, and a bit stressful when you know you have someones life in your hands sometimes.
But all in all, it's fabulous!!
Why, are you thinking of becoming one?