I really want to replace it with something like the Wave/Hive type app operated unit.
Why, not being funny, but I do have Drayton Wiser and Nest Gen 3, and the only reason I look at the app is to quote temperatures when answering a forum thread.
We had all big ideas, using geo-fencing, so heating auto turned on before we got home, and of course off when we left, but also turned off when wind damaged the local cell site, and since also a PIR in the Nest thermostat, which would turn heating back on when we walked past, we had a very cold day until we worked out what was going on.
The geo-fencing turned off OK, but we were nearly at the point of walking through the door, before it turned back on.
I am not using OpenTherm so can have multi-thermostats/hubs, but with OpenTherm you have just one hub, my worry was after a very cold narrow boat trip as the batteries were flat in the thermostat, that I should not be relying on batteries, to have multi-battery units OK, but to have it where one pair of discharged batteries means I get freezing cold is not my idea of fun.
I have given up on geo-fencing, I know my TRV heads and the Wiser can use IFTTT, but to be frank, can't see the point any more, simple times work better. Looking at 2 hours to reheat home, and so only time geo-fencing would work is when going on holiday, that's only time when away from home long enough to matter.
Now geo-fencing to turn on outside lights, that seems a good idea, saves me fiddling with my phone to turn them on when I get home, but as to central heating, I have on the odd times said hey google turn up living room heating to 22ºC which is does, but really easy enough to just use the touch controls on the room thermostat when getting up to make coffee. OK will admit the google command also sets the two TRV's as well, but they are normally set high enough anyway.
I made mistakes, main one was selecting Nest, the Drayton Wiser is better, I have kept Nest to work DHW, but the main problem was, be it Nest, Wiser, Hive, Tado, or Tapo, getting info about what they will do before buying is like getting water out of a stone.