It's been a while since I updated this post but development certainly hasn't stopped...
I've made significant changes to the heatpump controller by adding in predictive weather heating/cooling (there's another thread on this) and now an Android app.
I can now reliably control the system remotely via the app. Previously I used Telegram to send messages to the thermostat that then controlled the heatpump but this wasn't very reliable so I wrote my own app (that I can use to control the 3 heatpumps I have).
If anyone is interested, I used Basic for Android (
www.b4x.com) to write the app. It uses MQTT via CloudMQTT to talk directly to the heatpump controller.
Previously I controlled the heatpump via the remote thermostat but I decided to move the control back to the heatpump itself. The problem I had previously using Telegram is that it only works using SSL and this uses too much memory on the esp8266. Moving to MQTT has solved this memory problem so I could move the communications back to the heatpump.
Acuario