How difficult is the international foundation year?

Hi, I'm from Asia and I got into QMUL (LLB programme) with a foundation year. Same with University of Birmingham. QMUL requires me to score 70% and UofB requires 60%. If I don't achieve it, I'll not be able to start my course.

I know the education system in the UK is quite different than that of my own country and I'm not sure if I should take the risk (otherwise I'll apply to universities that don't require me to take an IFY).

So for anyone who did the IFY in Qmul, or have friends to did, can you tell me how achievable is 70%? Thank you in advance.