I'd let the Student Loan alone, neither reducing it now nor adding to it to make a margin. 

It's not a lot, but its your's, and its 'just in case'.  I would put it where you can get use of it when you need it, where it doesnot loose value, and where it can help you build up credit rating, as this is what would allow you to borrow when you want/need to later on.  Although the housing market is up/down just now, and you are not placed to enter it, it performs well in financial terms and has the side benefit of keeping you dry at nights.  I would therefore talk to a Building Society (and I would recommend the mutual Britannia BS - I'm not an employee) to get the best rate for a non-taxpayer, noting what happens if you have to take the money out in an emergency.

btw, I admire your grit.  mosty others here have found out how to spend money.