It's probably going to be on politics and whether you think 16 years should be able to vote and also on reforming the system, I mean, elections are every 5 years or something.
so if you got 10 mins just research arguments for and against 16 year olds being able to vote, do a quick search on politics etc. bring in examples.
GS is a piece of piss. You're doing A levels so you should at least get 27/30 on the multiple choice questions, that'll get you a D all on it's own, and those 3 marks will only be lost on something silly.
Just remember they're not trying to trick you - there wont be trick questions. Simples.
GS is silly, I don't even mention it when people ask what A levels I do because it's just so lol.