I'm a prison officer, and I work part time. However, it's my understanding that the service do not advertise for part time positions, it is full time only. You can only go part time once you're already working there, if that makes sense. I have 2 DC (14 and 12) and work semi part time hours (26 per week) as opposed to the 'normal' part time (19.5 hours).
It's a physically demanding job, be prepared to be on your feet for 12 hours, non stop. It isn't as exciting as you might think, the majority of the day (right now under COVID restrictions) is spent running the regime, so unlocking for meds/exercise/showers and dealing with prisoner queries (PIN phone applications, property etc). There is a LOT of self-harm in prisons, on a daily basis I see prisoners who have 'cut up', a lot of the time it is to manipulate staff into getting their own way (cutting up to get vapes is oh so common at my prison) it becomes the norm really, you aren't shocked by it after a few weeks. It does change you as a person, I hear so many sad stories that after a while, they all blur into one and you become hardened to it. You have to.
However, if you have good interpersonal skills, which I do, engaging with challenging prisoners and establishing a good rapport goes a hell of a long way and makes the job 10 times easier. I have learned that I am a far more patient person than I ever thought I was before I joined the service.
If you have any more questions, feel free to ask me!