Can I leave my Masters and start a different one.

I am a mature student and worked within a specific field. I loved it.
I have chosen a Masters in a field adjacent to mine, thinking it would be a nice reward for myself to pursue something else I enjoy for a year.
I hate it. I tried to leave in my first term, but was persuaded to stay by my teachers for one term to 'see how it goes'. I've now been told by student finance that because I've completed a term that I wouldn't be able to leave unless I switched to annother course in the university, but they don't carry my subject feild.

If I paid back all my student loan for the first term, could I start again somewhere else? I'm doing the work and getting 2.1s and 1sts, but its just not for me.