Thanks for the replies on this.
Switching or modifying the machine location didn't have any effect. We tried moving that in a few different ways.
The conclusion is that the room function does not work in EG mode. It needs to be run in general where we also got a number of pretty random looking errors. Those errors were created by custom window codes. So in order to use the room function we needed to produce a model with no custom codes and run it in general mode.
We got the results we were after seems like a silly work around.