Compelling personal reasons evidence

I went to university 09/10 to study computing, I was suffering from depression around that time and picked computing through clearing just to be doing -something- with my time. I realised about two thirds through the first year that I didn't want to be doing it, then stopped turning up and let it progress to a fail. I then did a year of working and deciding what I was going to do next year, eventually going back to my original choice of biology and science (which is what I picked my a-levels in). Now I'm due to start in September, but SFE want to see "Evidence of compelling personal reasons for not completing my course". I thought that you were allowed funding for 4+1 years of study anyway? Surely that means I should be able to get funding for another 3 years, as I've only had one year so far? What even counts as 'compelling'? That I didn't want to do that goddamn course? o.O