While it's true that usually a 2:1 is 60% and a First 70%, i think if you are coming from abroad you would have to assume that a 2:1 would be more like 7/10 or 8/10, though I'm not sure. I say this only as I have spoken to some Americans who tell me that is common for people to score 100% on exams and to have averages of over 80 or 90%, while in the UK university system that's really not possible. I may be wrong but achieving 80% on an exam here is really something special (at least it would be for me!) and most people's averages would be somewhere between 55 - 65%. So yeah, while i have no real idea what i'm talking about and it would entirely depend on what country you're from i would say a a 2:1 wouldn't translate as it's actual percentage of 60% but quite a bit higher.