Thanks Dan. I looked in the contextual menu. Didn't think to look in the entity window. There are at least three ways to do things in SU it seems!
I think I can do what I want within SU, at least, if not LO. In plan the name of the tanks will clearly sit over the model and move around with it as the winery is arranged. The name can be positioned so that it appears to hover above the tank in other views. and not whip around with the leader all the time ( I think). I can place it on another layer if I only want it showing sometimes.