Hmm. The issue seems to have resolved iself, I re-installed all pre-requsites, and it just seemd to work.
Although I did delete a folder in .minecraft called config, which may have had something to do with it?
It contained config files for various mods that I had, so maybe that was conflicting?
Seems unlikly but yeah.
Since I'm not used to this forum software, do I mark it 'solved' or does a mod do that?