I didn't study economics in school at all. I have done a LOT of post-graduate studying in it though, because unsurprisingly it is pretty core for an actuary.
My conclusion is that a little bit of understanding of it is a very, very dangerous thing. A-level economics does little more than brush the surface, which means that it leaves students thinking that free markets have the answer, because the complications to these ideas require rather more understanding than the A-level curriculum really allows for. And GCSE is even worse.
Since I don't think the issues can ever really be covered in sufficient detail in a basic course and since I am convinced about this "a little knowledge is dangerous" issue, I'm not convinced it is a good thing in schools, actually. The basic macroeconomic issues (of things like how inflation and interest rates are linked) could be covered in a general studies course. But all the microeconomic misunderstandings that basic supply-demand curves teach would be well to be left alone.