Hi, can anyone give me any advice please. I have had my grey for 2 months now. He is great with my lab x and other greys but not so great with any other breeds. Doesn't matter how big or small the other dog is he barks and tries to get to them on walks. The rgt I had him from said it was a socialization issue. I don't think it helps that he is taunted by a jack Russell that breaks into the garden at night. Any ideas?