There have been several questions here about contemporary European views of the American Civil War, but I'm referring to present day viewpoints. The Civil War shaped the history and culture of the United States in huge ways that many books have tried to elucidate. Long story short (too late), the war mended old divisions and created new ones that still exist today, helped consolidate the fractious antebellum politics, and gave new energy to the idea of America as unique (Manifest Destiny). Culturally I think the war is perhaps the largest influence on the collective memory of the US because of the fraticidal nature of the war, the issue of slavery, economic effects still felt today (Reconstruction), etc. So how does the international community learn about the American Civil War? Do they see the effects of it or see how it has shaped the US and its culture? How is it taught in school, if at all?
I can't comment on A level as I have no experience of it, but at GCSE (roughly US high school diploma level) it doesn't tend to get taught.
This .pdf shows the provisional modules for GCSE History A and B from the exam board OCR. As it shows, only one of the modules, The Making of America 1789-1900, from History B covers America during the necessary period.
As it's part of Paper 3, which is predominantly source based, the actual teaching of what happened in that period will be reduced compared to the content of Paper 1, with more emphasis on the reading and evaluation of sources from that period.
Finally, the syllabus itself requires that a certain proportion of the course is British history (with about 2000 years to choose from) and a certain proportion is worldwide, though this tends to either empire or superpower relations/Cold War. Within that remit there's not much space for a four year war that didn't involve or affect Britain.
I grew up in Ireland and went to school in the 1980s. We didn't do US history at all. The latest syllabus covers only US influence on the world after 1945. We did have it available as a survey course in university.
I think the rationale is that while domestic US history is interesting, it is not as important as that of our European neighbours. There would be a certain degree of knowledge of the civil war especially from the Ken Burns documentaries and Spielberg's film.
Here in Brazil I can say that it is mostly ignored. When we talk about the US in history classes, it's a bit of the Independence movement and how it connects with the French Revolution and the other Independence movements in South America, then nothing until World War I and II and the Cold War.
EDIT: That of course is in the basic level of education, not in the college level.