I stopped using bottles with teats during the day from around 12 months, but neither of mine were big milk drinkers so it wasn't a big deal. They never had juice or water from bottles anyway (my big pet hate, sorry to anyone who does it). We used the soft Avent spouts in the bottles as a bridge to using cups for milk. They ate a lot of dairy stuff, and had lots of milk on their cereal, so I was never that concerned if they drank other stuff instead.
I think its got to be more difficult as they get older, they understand what they are losing! I had the same battles but with dummies, and it is hard. Its probably a bit late in the year now, but with ds2 I got rid of his dummy when we went on holiday, I told him it had got lost on the airplane. He was so distracted by being away that it worked. My BF suggested it after she tried the story on her dd.
Hope this is at least a bit useful, good luck!