I use a Honeywell Evohome Smart system with motorised valves on all rad's. The system can heat just one room in the house if required, so only filling one rad not all of them!!
The system can control the boiler output to heat just enough water to fill one rad then switch off.
To get this working you need a "Open Therm" compatible boiler (Mines an ATAG ic27) and the wireless bridge interface to control boiler.
All (most!) rad's can be retro fitted with the Wireless controllers.
https://heatingcontrols.honeywellhome.com/products/Connected-Smart-Products/evohome-connected-thermostat/evohome-Main/
Thanks for the information, very interesting, although other similar systems are available, Honeywell Evohome would appear to be the "Rolls Royce" option, certainly not cheap.
My TRV's are mostly quite old Danfoss RAV 26mm series and suitable adaptor selection is quite complex if indeed possible, might be easier to completely replace the TRV bodies.
Would certainly be over £1000 to fully upgrade my CH/HW system but certainly a lot easier and very likely less costly than trying to modify existing pipe work to fit zone MOV's.
I like the feature where an additional room stat can be utilised to override the radiator TRV, would think that would give better area temperature control and stop the radiator "chasing it's tail" with temperature cycling and not accurately reflecting the actual room temperature.
Of course this addition would certainly add to overall cost.
