You are right, I was wrong, I am sorry. There exist analog I/O and relay contacts.
I was misled by the same fact that you depicted above, “tank pump…” and then no relay settings. I could neither set it in VEConfigure, because I am on ESS assistant and this does not allow me to program Virtual Switch functionality (I think to use any assistant you need “Do not use VS”).
Tweaking VEConfigure settings, there are some relay assistants (programmable relay 012C etc), but as you found out, I do not see any programmable temp set point (only on/off). Neither I see how we can make use of the analog I/O.
wrt the video that Owen sent, I have no clue how to reach those menus (I/O and Relay) - if at all I can, on our embedded cerbo board. Anyone?
Looks to me everything is pushing for nodeRED.
Dimitris, no problem. Hopefully NodeRED/Shelly will provide the solution 
Hi Owen,
Can I kindly take you up on your offer for help.
I have set up a Shelly 1 Mini Gen3 and tested it on the Android App to confirm it works and it’s IP address. Here’s the Nodes…
And here are its properties…
I’ve tried injecting True/False and 1/0 but no response despite being told 'Successfully Injected True/False/1/0.
Any thoughts?
This works for a shelly pro 1pm. I don’t have any gen 3 and the payload is slightly different. See if this works but you might be able to figure it out once you see it. I also have a function that will turn on below 5 and off above 10 so that you can inject the temperature to control the heater. Adjust the values as required.
Flow is in the text document.
shelly control.txt (12.1 KB)
Now this is what these forums are all about. Good Solid advice!
Works a treat! Now I’m away and creating.
Thank you so much!
Paul from Bolney in the UK