SITL Gazebo Broadcasting

My old account seems to have disappeared. Any way, after a couple of years away from it all, I’m trying to get PX4 gazebo running but can’t sort out how to get it to broadcast (simulation running on one computer, QGC on another). It seems the parameter changed to MAV_x_BROADCAST but changing it has no effect. If I run QGC on the machine running gazebo, I can’t find any BRO* parameter. Any pointers?