Got #homeassistant installed and connected to my MQTT server. Successfully detected 300+ devices - everything except my #zigbee switches it appears. If I can't get them into HA, there's no point in even thinking about trying to migrate from #nodered.
More tinkering tomorrow, I think.
OK. Managed to work out how to get the switches onto the dashboard for starters.
Now I need to work out how I'm going to code for the 24 switches with 77 buttons and 231 possible button presses. This was easy in NodeRed. I suspect it won't be in HA.