Although I'm on track to getting a First in Bsc, there have been few modules that I messed up along the way. Stupidly one of them is in the area I would like to do the Phd in (I'm interested in neuropsychology and I got grade 3 for Biological Psychology). Do the universities care about the individual grades or are they more interested in the overall classification of the degree?

The reason I got a bad grade is because I was not well prepared - I didn't have the basic knowledge of human body back then. But I have caught up since, and perhaps because of me trying to catch up I realised that biological psychology/neuropsychology is what I want to focus on in the future. But I still have grade 3 on my transcript.

Also, given all the MOOC courses available nowadays (Coursera, EdX, ...), would it be useful for me to take a certified course in the similar area (e.g. neuroscience)? Do the universities even consider such certificates?

Thank you.

I don't think it matters too much, as long as you didn't retake them to get a better grade, or failed some completely. Especially if they were first year modules, which I'm assuming they were since you will struggle to get a First if you get less than 60% in a module during your second or third year. [I don't know what grade 3 means].

If you get a First, they probably won't care at all anyway.

I don't think MOOCs are considered as 'real' qualifications at the moment, but at least they will show a willingness to try, so they can't hurt.