RPSMs are the specialist revenue protection team. Often see them out doing station blocks, on train revenue exercises, that kind of thing. They issue Penalty Fares, report for prosecution; they always struck me as a professional bunch back when I used to commute on LNRs off Liverpool. They don't manage staff directly as far as I'm aware but they work really closely with other staff eg Gateline, Conductors, Station Security etc to reduce ticketless travel through stuff like gathering intelligence. Probably a lot of likelihood of abuse unfortunately given that the sorts of people who intentionally don't buy tickets are often the same people who are violent towards the staff, but if you're able to deal well with conflict it probably isn't too bad a job, plenty of variety.