Okay, that was even more confusing for a little while, until I realised I was reading the user guide for the Gen 5 model, which has:
The device supports several (key numbers +1) association groups (AG). The 1st AG is used for
reporting devices’state to the controller if any changes happen. This group supports one Node, which
suggested to be controller Node. The rest AGs are used for switching associated devices,and they
can support up to 5 nodes each.
When I included the pre Gen 5 version yesterday it was set up as Group 1 associated with the controller. That looks like a correct set up for Gen 5, but not pre Gen 5.
If anyone else is till reading this
If you get a new, Gen 5, version it should work out of the box, but I don't have one and cannot test it.
If you have or get a pre Gen 5 version, e.g. MH-S314 for the 4 gang, then you will need to apply the fix Peter details in this thread. I'm assuming that removing the Group 1 association (associated with controller) would be a good thing to do, too.
Sam