Keep going, you've acheived so much.
I don't know whether this will help you or not, but whenever I feel like stuffing my face, i keep telling myself 'They are not going to run out of ....' (hot chips, chocolate etc etc', and then imagine looking at myself in the mirror when I am at my goal weight, in my new clothes. This seems make me think twice about what I am putting in my mouth, and reconsider.
Hope this helps a little. I only managed to lose 100g over Christmas week, but I figure that any other Christmas I would have gained weight.
Keep at it.