I work for the NHS and we are merging with another organisation. I've been advised by my line manager today that my post is under threat as there are two of us doing a similar role. This comes just a week after they interviewed for someone new to do an identical job, they haven't started in post yet. I am currently managing 2 teams including the one they just interviewed for. Do you think I might have a grievance here? My track record is impeccable by the way. I am in a union and will contact them.