has revealed that I'm paying off my student loan without realising it. At least, I'm guessing that's what's going on

Under deductions, it just says rather simply "Student loan - 34.00"

I don't ever remember signing anything or filling any form in. To be honest, I know I haven't, because I was actively putting off paying any of it back until next year some time

How does this happen then? Is it just what always happens when people ignore the repayment forms? I get paid into a different account that I got my loan paid into, thinking about it. Maybe they snared me with my national insurance number, the swines