I want to keep this issue updated in case it's useful to other people (especially as HEM's seem to have lots of issues).
Been checking the Aeotec HEM Manuals and the one supplied with my Aeotec HEM's and the downloadable one are different! Also searching other Forums turns up information not listed in either manual.
1/ My Manual says when you exclude the device it factory resets. Well, I discovered somewhere online, if you hold down the button for more than 10 seconds, it will do a full factory reset. I never did believe it was done by removing the device from the network as the manual says.
2/ If you press the button twice in quick succession while joining it will include with security (Again can't see this in the Aeotec Manual). The hub still doesn't offer security options but it did join securely and found the Driver (ClassicGod version) straight away.
3/ Trying to set up the parameters again and it stops at exactly the same position:
" in progress (parameter: 7) ". At least this time it doesn't send stuff every 5 seconds but it doesn't update anything unless you click refresh.
So I am no further forward after 6 include/excludes attempts.
The built-in driver didn't work for me at all and having contacted Classic God he assures me his driver should work fine for UK single and 3 clamp versions on Hubitat.
The next step is to contact Aeotec support and see what they have to say.
As always any advice or ideas welcome
