I remember seeing a site somewhere that sells Hogwarts robes, but I can't remember if they had Slytherin ones. I know they do Hogwarts dressing gown robes, tempted to get one when I get a job
Thanks for the link, I do like that robe, but I'm after a more authentic looking robe, it's a shame the more real-looking robes are either over £100 or only in children's sizes.