Second Degree in French and Korean?

So it's a long story, but basically I have a 2:2 degree in biology, but my real passion is languages (hence the 2:2, lol). I'm proficient in Korean (~B2/TOPIK L4) and would like to do a second degree in French and Korean; Korean because I love Korean, and French because I want to have teaching modern languages as a possibility (which will either make sense or sound incredibly ironic to you when you finish reading this accidental biography). The problem (besides cost and feasibility, but I'm unreasonably optimistic about funding it myself) is my lack of language qualifications. My school had a staff shortage while I was there (undesirable area of Scotland I guess) and studying a modern language was not an option for me, so I have no Higher in French with which to apply. What can I do to show language proficiency? I can't seem to find any make up courses for French like I can for Maths and English...would a B2 language certificate be reasonable (approx. A Level French as far as I can tell), or Open University modules? Even better (i.e. cheaper) if I can do a year's worth of credits with the OU, but I don't think this is possible for French and Korean, right? Abandon Korean and just do French with the OU?

TL;DR I should probably just call the few universities that offer French and Korean and ask how I can qualify. But if anyone has experienced a similar situation I'd love to hear what you did! Or if you just wanna knock some sense into me...my friends are telling me this is all a waste of time and effort anyway.