A couple of weeks ago, we told our employer that we were planning on migrating to New Zealand late in 2017, saying it was only fair we gave them as much notice as possible (a year). Today, I found out that they have secretly re-emloyed an ex employee (I shall name him Bob for the sake of this topic). Bob was employed when I started in March 2014. he seemed to have a split personality, one day he was happy, the next he was very moody, and often took it out on me. Bob didn't seem to like me for whatever reason he had and it was uncomfortable working with him to the point I was considering my options. I loved my job but I felt I was treading on eggshells whenever I was working with him as i’d never know what kind of mood he was in. I decided that it would be best to try to just get on with it and keep my head down. I made it clear to my employers that I was uncomfortable at the time. In the end, Bob walked out of the workplace during an evening shift in September 2014ish, blaming me, saying how he hoped I would get sacked and how he wanted to slap me. Since then, I have loved working at my workplace and we have a great team in the kitchen (for almost 2 years the same team) and have had no issues since Bob quit. I don’t know the motives for bringing Bob back, why would you re-employ somebody who walked out on you? Surely my employers know it’s going to cause friction in the workplace and I already dread the fact I am going to have to work with him to the point i’m considering giving my notice. I am very popular at my work place and have built a fantastic reputation for our food and a lot of customers love me and always comment when i've been on holiday how it just hasn't been as good. My question is, if i do feel that i cannot work here with Bob, and i quit my position as a direct result of my employers actions, do i have a case for constructive dismissal? What kind of evidence do i need to bolster it up?