I have literally this week been promoted from SEO to G7, on my second attempt.
I agree with the PP about results and reflection. I focused on the results part of STAR the most, and my feedback was all about how 'she clearly demonstrated the impact of her actions and decisions, not just on her immediate area and team, but on wider departmental strategy and approach'. Going into the interview I was advised by my manager that at G7 level they are looking for evidence of genuine impact - in terms of your actual work, yes, but also in terms of how you influence, persuade, mentor and lead more widely. So come up with concrete examples of those - how you thought about an issue, what action you took, why you took it, and what impact it had.
One thing I found really helpful when preparing (and I checked that this was acceptable AI use beforehand - which it is in my dept; may be different in yours):
I fed the job description into ChatGPT and Gemini (they came up with different responses) with the following prompt:
"I am applying for a position as a [job role] in the UK civil service. Read between the lines in the job description below, then list out each of the essential criteria one by one, and tell me what skills, behaviours, qualities, traits, attitudes or prior experience you are looking for, and suggest ways I can best demonstrate them.
Respond as though you are a panel of [senior policy advisers or whoever will be interviewing you] with decades of experience in both working with and interviewing for [the role you're applying for]."
Honestly, the responses were so useful for helping me to organise my thoughts around each of the job requirements and desired experience/behaviours. Once I had finalised my examples, I also asked ChatGPT to sense check that they accurately reflected those points.
Note: I did not use AI to embellish or exaggerate my examples in any way, just to check I was hitting the right points. Eg, I'd say 'Read this example answer and tell me if it demonstrates my ability to [lead a complex project] in a compelling way. Pay particular attention to how I have talked about my actions and the impact of them. Have I successfully shown how I [take responsibility, think strategically, navigate complexity, share knowledge, influence tricky stakeholders, improve efficiency]? If not, how could I make it better?"
This just helped me to finesse my examples, and by doing this work and reading through them all so many times, I was able to deliver them much more fluently and confidently in the interview.
Good luck, OP! Let us know how you get on.
(By the way, my interview wasn't conversational at all - it was very structured, with set questions, and there was no veering off from that. May be different in a policy role - I'm in a tech role.)