Thanks for your answer. Administrators is a pretty big umbrella. That covers everything from Border Force staff providing immigration and customs services to officials in Parliament. Do you have any specific groups you'd target?
HR, as unhelpful as I find them at times, provide a pretty fundamental role in ensuring business critical processes such as recruitment, performance and dismissal run smoothly and minimise risk to the business. I wouldn't want to run a poor performance process as a manager without them.
Social media feels less critical and I agree this is probably where I would look but how do you raise awareness of policy changes without them?
Had a look on Civil Service Jobs as you suggested but struggled to work out how many diversity vacancies the Civil Service has to be honest. Loads of adverts come up for diversity but that's not because they are diversity specialists. One was an IT specialist. It must be because of the standard job advert wording which says they're an inclusive employer.
I've also had a look on the civil service jobs website for interpreters and I found 0 adverts. Of course you have conflated central and local government (local government aren't the civil service and don't use civil service jobs) so maybe you were thinking of local government or NHS? They're wider public sector though, not civil service.
I think you'd find it a lot harder to cut 25% of civil servants than you realise.