If you're looking to work in the UK, Durham. If you are looking to work in East Asia, you need to go to the most highly rated university in order to have the best chances of success. However, in Singapore, consideration is given largely to whether the university you attended is on the government's list of acceptable universities and after that, the university you attended is not much considered (for non-Oxbridge/LSE/UCL grads anyhow). The main assessment is whether you performed well, whether you achieved 65%+. I don't think Birmingham will be any easier than Durham as regards grading. In fact the lack of guided-learning -- as is present at Durham -- could be argued to make it more difficult to do well in Birmingham than Durham. It's a very complex question you have asked and really you'll be okay no matter what university you go to, assuming you perform well there.