Reading what you both say, I think I should say in hind sight, I wish I had not gone for cheap option and had gone for EvoHome from start. However EvoHome as said seemed expensive, so I wanted to get better control for late mother's house, now mine.
So my mistakes, so hopefully you will not make the same errors.
1) Cheap programmable wireless thermostat, problem was there was no fail safe, so lost RF link and found house at 28°C when it failed to turn off. Cheap wired OK, cheap wireless no good.
2) Expensive wireless thermostat with fail safe, also had anti-hysteresis software so it keeps turning heating off/on which does not help when located other than main room.
3) Mid priced electronic heads for thermostatic radiator valves, at £80 a pair not cheap, plus needed hub, with the thermostat switching off/on they tend to open when boiler not running, then take a bit too long to close when boiler starts to run, so needed careful adjusting of the lock shield valve to stop them over shooting, this in spite of the anti hysteresis software meaning change temperature from 16°C to 20°C and quite rapid getting to 18°C but then can take 2 hours to get last 2°C.
It seems only a Wave thermostat with work with my boiler to modulate it, Worcester Bosch have not gone for OpenTherm so unless I change boiler there is only one thermostat which modulates. However Wave only sets temperature in one room, and I wanted to control temperature in at least two rooms, my idea was simple, use TRV (standard type) to stop room over heating, and then use two thermostats one in night room and one in day room with timers so it switched from one to other. Idea was sound, let down by faulty thermostats.
I found the standard TRV is not very accurate, when the wall thermostat stuck on, room may have reached 24°C but should not have hit 28°C the electronic heads cured this, however the time taken for change i.e. heat stored in fabric of room, means in real terms day temperature and night temperature, even if it can be set for geofencing, room temperature change time means all the internet connecting was a waste of money, I could have bought electronic programmable heads non wifi for under £20 each there was no need for internet, although before moving in with mother, being able to monitor temperature was good.
So hind sight Terrier i30 would have likely been just as good as my Energenie TRV heads and a lot cheaper, I had intended to fit Nest later which works with Energenie but since can't use the OpenTherm never bothered. And I should have got the thermostats hard wired when house was rewired then I could have used cheap programmable thermostats instead of expensive wireless types, so the boiler would not be switched off/on so often. Or I should have gone whole hog and used EvoHome.
Yes what I have now works, and works well, however it took ages to work out how to set up and get it as it is now.
So for you, I assume you are trying to save on heating bill by not heating rooms when not in use, you already have two zones, so to improve on that you need more zones, and the easy way to get more zones is the electronic head on the TRV. So £13 per radiator for cheap i30 or hundreds of pounds for EvoHome, don't get me wrong, if I buy another house and it needs new central heating it would be OpenTherm boiler and EvoHome, but with what I know now, with this house, stuck with a non OpenTherm boiler, I would use two or more hard wired cheap programmable thermostats, and terrier i30 heads. If I want ability to switch on/off with internet, I would use a relay, i.e. simple on or off, I have no need to alter temperature remotely on/off is good enough. OK frost stat across relay contacts to stop freezing.
So either go for full automation, or go for cheap, going for cheap leaves you with a few hundred to spare, so the odd time heating comes on too early will not really matter.
