I use the drayton trv’s but I would not recommend this route. Reason being that the earlier version firmwares work fine, the later do not due to a change in functionality which make them incompatible with 3rd party systems. I chose to take the route with more aggro, but cheaper, i.e. I bought and returned so many of these from amazon that eventually, I had enough of the appropriate firmware ones (I have 7), that it all works.
It was cheaper (£35 a shot), but when one eventually fails I’ll probably have to go the route of replacing with a smartthings compatible Danfoss lc-13 (more expensive) (https://support.smartthings.com/hc/en-gb/articles/115000152443-Danfoss-Living-Connect-Thermostatic-Radiator-Valve-LC13-)
With a bit of webcore tinkering, the control is immense and wouldn’t swap it for the world. For example, my wakeup alarm (smartapp) gives the heating a boost 30 mins before wakeup… when one of us is on the way home, the heating gets a boost within 1 mile… heating disabled when alarm is set. Etc etc. I love it, but I knew it would take a bit of work to get up and running.