Applied online via Civil Service Jobs.
Invited to interview several weeks later via Google Meet.
Just run of the mill Civil Service Competency questions (Civil Service HR has given the framework a new name, but it is still overwhelmingly the same), my advice is to read through the supporting documents you're sent beforehand.
Asked what I understood by OSINT;
I used OSINT to research members of my panel beforehand and learn about their past military service, civil service careers, work in their community, and how most of the existing team/department are ex-military.
... I also used OSINT afterwards to find that most of the panel spent my interview (and most of the rest of the day's interviews) looking at their own social media, tweeting memes, and re-tweeting anti-corbyn/blairite messages.