Reapplying to uni after alcoholism

Hi guys,

I want to apply for uni again after struggling with alcoholism and then going into recovery. Unfortunately the onset of it was during my A Levels in which I got a B in English Lit, D in Philosophy and a Pass in Music Performance. I managed to attend one year of university in which I got a 2:1 overall studying philosophy, but eventually had to drop out due to the aforementioned addiction.

I want to study media at UCL, but I was wondering if the grades I achieved at A Level would significantly handicap me, or whether my first year university grades would be taken into account. Essentially I just wonder whether it would be worth applying or whether I should broach the subject of my low A-Levels by mentioning alcoholism. I'd be applying as a mature student now as it's taken me a fee years to get back on track