Marking inaccuracies affecting my degree classification!!

I would say you probably have, yeah. Particularly if a majority of your modules were 2:1 or 1st

They were mainly 2.1s this year, last year they weren't (they would have been for the essays in the modules, but last year I was sick during exams and they brought most my module marks down to 2.2s, I had submitted medical evidence for this however). I do sociology and anthropology, they told me in anthropology that due to being unwell if my mark was very close (i.e. 59!) I might get a chance to have my mark pushed up, however it is sociology who decides on your final mark and I'm wondering whether this medical evidence wasn't passed from the anthropology department to the sociology one like it was meant to! Guess I can inquire about that too, no harm in trying after all!

It depends. If your uni has a stated policy that marks will be rounded up (usually in the range 0.5-0.9) or down (usually in the range 0.1-0.4) to the nearest whole percentage, then they've followed procedure, you've been subject to the same marking scheme as everyone else, and you have no grounds for appeal.

Check the small print before getting your hopes up.