steve, 
Setting up #HomeAssistant to fiddle with. First impressions - very bad. Booted up the HAOS image, it immediately autoupdated with an update that included a breaking change. https://community.home-assistant.io/t/home-assistant-400-bad-request-docker-proxy-solution/322163/23 describes the fix, but requires knowledge I don't have:
"Edit the config file" - doesn't say where the config file is.
"Check the log" - doesn't say where the log is.
"Find the IP address with "docker network inspect"" - there are lots of IP addresses, which do I need?
Argh!