I'm applying for PhD's (from the UK) with a low 2:2 BSc and a Distinction MSc, and performed very poorly in a few certain modules of my undergrad degree (including failing two 3rd year modules) which pulled my grade down. In my MSc research project and the MSc modules most relevant to my PhD field of study, however, I obtained high firsts (80%+).
I'm taking online courses on the failed undergrad topics on edx and coursera to strengthen my previous weak points and fill the gaps in my knowledge. Is it worth highlighting this in my application, and if so, is it worth paying for the verified certificates? I'm aware of the general opinion that mentioning MOOC's in a SOP isn't detrimental but does little to strengthen an application - in my case, would it at all counteract the bad module marks?