pallan: While it's correct that the numbers are stacked against you, someone will get the job and there's no reason why that couldn't be you. Certainly applying increases your chances of being selected than not.
Your debt argument seems pretty logical. However, I'm not sure if you would end up in as much debt as you think. Would you really have a £50k student loan to repay even if you only did a year of the degree? I was under the impression the funding was given to the institution in installments, and therefore any such payments would cease if you left the degree and you wouldn't be eligible to repay those. On that basis you'd only be due to pay about a quarter of the loan that you would have been due to pay had you stayed for the whole course.
Anyway, good luck!