I will tell you what I have, which is not ideal, I have the wireless electronic head made by Energenie under the MiHome label. They require an expensive hub, they can be used with Nest using IFTTT and follow commands, even be set when the phone is within a set distance or when weather forecast says temperature below set figure, and manually using a phone app or PC, however whole idea is to automate so manually adjusting with phone seems a bit daft.
They do have some good features, like two sensors one for water and one for air so temperature of the radiator is compensated for, and yes room set to 20°C and room actually stays at 20°C however after fitting I also found the down side.
They have built in anti-hysteresis software, and yes it works, however if to set it to raise room from overnight 16°C at 6 am to 20°C by 11 am it has just about got there, I have to set it to 23°C at 6 am and at 8 am when it will be around 20°C change setting again to 20°C which it will then maintain. I had not realised it took 2 hours to raise the temperature from 16°C to 20°C even with the cheat, and to be frank I have had very few jobs where I would travel for 2 hours to get home 14 hours yes, 2 hours no. So the automated system using phones GPS is useless as I don't live far enough away from work.
Also one has to fiddle the boiler to fire up as well, I was going to get Nest, but in the end just used a standard programmer set to switch on at same time as the electronic TRV heads change temperature.
So in hind sight and that is so easy, the Pegler i30 would have likely done the same job and cost a lot less, there is really no need to alter them from phone or PC, in fact not having to boot up PC to adjust temperature when mother is cold would be likely a plus.
So I would say either do it on the cheap with Pegler i30 or go whole hog with EvoHome. What we need to consider is unless the Boiler is OpenTherm enabled or similar then a wall thermostat switches it on/off and what we want is for the boiler to be varied up/down and only when it can't go down any more do we want to start using a mark/space ratio to adjust output. So with most condensate boilers we want to control the return water temperature which in turn controls flame height, the EvoHome even when not connected to an OpenTherm enabled boiler does this. Quite simple if target is above current on any eTRV then boiler runs, if all targets equal or are below current then switch off boiler, so if one room changes target temperature to above current the boiler runs. Using Nest with my eTRV all would need to be set to same temperature so rather defeats the whole idea of having rooms at different temperatures. My reading seems to show only EvoHome does this. However trying to work out what Wiser or Tado does I gave up, same with the Bosch Worcester system. The paperwork is so poor on what it does. Hive is really useless yes it has internet, but will only work volt free with heating only, if used for domestic hot water no volt free option, Nest is better, it is volt free and it is OpenTherm and it can follow or be followed with IFTTT. However why bother spending that money on a half hearted system?
I also looked at underfloor heating controls, and it does seem they have something like a eTRV head which is hard wired, however it has just two modes, on/off where the eTRV slowly increases or decreases flow. It seemed the Myson fan assisted radiator what best option with variable fan speed to control temperature, however then I saw the price of the building management system, yes it could also control cooling but my pockets are not that deep.
So in hind sight if I was doing it all again I would not bother with WiFi I would get the Pegler i30 stand alone units and save a lot of money, or of course go whole hog and use EvoHome, and from what I read EvoHome does not NEED a hub, or any internet, it can be set stand alone.
